First year

McGuinty took office as Premier and Minister of Intergovernmental Affairs on October 23, 2003.

The new government called the Legislature back in session in late 2003. The government brought in auto insurance reforms (including a price cap), rolled-back a series of corporate and personal tax cuts that had been scheduled for 2004, passed legislation that enshrined publicly funded healthcare into provincial law, hired more meat and water inspectors, opened up the provincially owned electricity companies to Freedom of Information laws and enacted a ban on partisan government advertising.

On May 18, 2004, Provincial Finance Minister Greg Sorbara released the McGuinty government's first budget, the first year of a four-year plan focused on tackling four deficits the Liberals claim the previous Tories left behind: the "health deficit", the "education deficit", the "infrastructure deficit" and the "fiscal deficit".

This budget was focused on health care. At its core was a large infusion of new money into hospitals specifically to shorten wait times in key areas: knee and hip replacements, cancer treatment, cardiac treatment, cataracts, and MRI and CT scans. The government also brought in free immunizations for children, 150 new Family Health Teams to improve access to physicians, almost 100,000 new home care spaces for Ontario's elderly, almost 4,000 new long-term care beds, and $200 million more to improve public health and fight potential outbreaks like SARS and West Nile fever.

To pay for this plan, the Liberals imposed a controversial new Health Premium of $300 to $900, staggered according to income. This violated a key Liberal campaign pledge not to raise taxes, and gave the government an early reputation for breaking promises. The Liberals defended the premium by arguing that the previous government had a hidden deficit, and McGuinty claimed he needed to break his campaign pledge on taxation to fulfill his promises on other fronts. His own finance critic of the time, Gerry Phillips, had predicted that the Tories' projected balanced budget would in fact result in a $5 billion deficit in a meeting of the Standing Committee of Estimates of the Legislature on June 3, 2003.^[23] Liberal MPP Monte Kwinter also predicted a $5 billion deficit.^[24]

As a result, the Liberals dropped badly in polls and McGuinty fell behind Ernie Eves in the category of preferred premier.^[25]

The Ontario Health Premium also became a major issue in the early days of the 2004 federal election, called a week after the Ontario budget. Many believe that the controversy hampered Liberal Prime Minister Paul Martin's bid for re-election .

Also controversial was the elimination of coverage for health services not covered by the Canada Health Act including eye examinations and physical therapy. Other elements of the McGuinty government's first budget were a four-year plan to tackle the deficit, funding for 1,000 new teachers, a transfer of two cents of the existing gas tax to municipalities to help fund transit, and a three per cent increase to those on social assistance, the first increase in ten years.

Soon after the federal election, McGuinty attended a First Ministers' Meeting on health-care reform that resulted in a new agreement for a national health accord. This Accord saw the provinces receive new federal funding in exchange for providing reports on such things as waiting times for surgeries.

McGuinty's government ended the year by releasing "Progress Report 2004: Getting Results for Ontario". This work focused on health, education, and economic growth, and set targets to achieve before the next election (including reducing the high school drop out rate, increasing participation in post-secondary education and reducing wait times for specific medical procedures).

Second year

The McGuinty government brought forward a number of initiatives in the fall of 2004. These included legislation allowing restaurant patrons to bring their own wine, banning junk food in public schools, outlawing smoking in public places, and requiring students to stay in school until age 18. Following a series of high-profile maulings by pit bulls, the government also moved to ban the dogs. Some Ontarians were critical of this issue since it was seen as moving the responsibility for safety away from owners and over toward the animals. People who owned pitbulls previous to the ban were allowed to keep them, muzzled in public and sterilized to prevent them from breeding. The "importing" and breeding of pitbulls in Ontario was banned, while all pitbulls being held in shelters were euthanized or sent to research facilities.

During early 2005, McGuinty called the Legislature back for a rare winter session to debate and pass several high-profile bills. The government legislated a "greenbelt" around Toronto. The size of Prince Edward Island, the Greenbelt protects a broad swath of land from development and preserves forests and farmland. In response to court decisions, the McGuinty Liberals updated legislation to reflect the change in the definition of marriage to include homosexual couples.

McGuinty also launched a campaign to narrow the so-called "$23 billion gap" between what Ontario contributes to the federal government and what is returned to Ontario in services. This came as a sharp turn after more than a year of cooperating with the federal government. McGuinty said special deals made by the federal government with other provinces (Newfoundland and Labrador and Nova Scotia) compromised the nature of equalization. He noted that immigrants in Ontario receive $800 in support from the federal government, while those in Quebec receive $3,800.

Premier McGuinty and Prime Minister Paul Martin debated the Ontario government's accusations throughout the spring of 2005.^[26] McGuinty and Martin finally met in May and, following a nine-hour meeting, McGuinty received a commitment for $5.75 billion, spread out over five years, including new money for immigrant settlement, training for the unemployed, federal delivery of meat inspection and corporate tax collection and per capita funding for post-secondary education.^[27]

In late April 2005, McGuinty announced the closure of the Lakeview coal-fired generating station, one of Ontario's largest polluters. Although the McGuinty government had promised to close all coal-burning plants by 2007, Energy Minister Dwight Duncan announced on June 14, 2005, that this was no longer possible, and that the Nanticoke Coal Plant will not close until 2009.

On May 11, 2005, the McGuinty Liberals delivered their second budget, built around the "Reaching Higher" plan for education. The second year of the four-year plan, this budget was designed to tackle to so-called "education deficit". Investing $6.2 billion over the next four years, the budget included the largest investment in higher education in forty years. It also increased accessibility for low-income students, expanded medical school spaces, and invested in new faculty, graduate scholarships and research. The budget also broke a promise to balance the budget in 2007–08. The government instead aimed at balance in 2008–09.

The McGuinty Liberals also moved to expand infrastructure spending by encouraging Ontario's large pension plans to invest in the construction of new roads, schools and hospitals. Specific projects in the budget included a 10-year expansion of the Toronto Transit Commission and GO Transit, 15,000 new affordable housing units and improved border crossings. NDP leader Howard Hampton described this move as "privatization by stealth".

During their second year in office, the McGuinty Liberals brought forward a series of negotiations with the province's unions.First, Health Minister George Smitherman concluded an agreement with the province's doctors that included incentives to practice in family health teams or under-serviced communities. Education Minister Gerard Kennedy established a province-wide negotiating framework with the province's teachers' unions with the result that most school boards settled their contracts without lost teaching time. Finally, Management Board Chair Gerry Phillips closed a deal with the provincial government's own civil service union, the Ontario Public Service Employees Union.

On June 22, 2005, Education Minister Gerard Kennedy announced that 90–95% of Ontario students between junior kindergarten and Grade Three would be in classes of twenty students or fewer by 2007. He also acknowledged that extenuating circumstances may require slightly larger classes in some cases. Opposition critic Frank Klees accused the McGuinty government of breaking its promise to cap classroom sizes. Kennedy responded that some flexibility is always necessary, and that any reasonable person would regard a 90–95% success rate as a promise kept.^[28]

Also in June 2005, two cabinet ministers in McGuinty's government were scrutinized for alleged improprieties. Joseph Cordiano faced calls for his resignation after revelations that he billed $17,000 for personal expenses to his riding association. These expenses included meals in Paris and Milan, and theatre tickets in London. Cordiano insisted that these expenses were related to riding activities, and refused to resign. McGuinty defended Cordiano in public, claiming he had "complete confidence" in the minister.

At around the same time, Minister of Transportation Harinder Takhar was accused of a conflict-of-interest, after visiting a company that he owned in a blind trust. Takhar acknowledged that he made "an error in judgement", but denied any wrongdoing. Both Cordiano and Takhar were retained in their portfolios following a cabinet shuffle on June 29, 2005. The matter was sent to the provincial ethics commissioner, who on January 4, 2006, ruled that Takhar had violated Ontario's integrity guidelines by not maintaining an arms length relationship with the trustee appointed to run his blind trust. McGuinty has defended his minister, and has rejected calls to remove him from cabinet, even after the Integrity Commissioner issued his finding.^[29]

In the same cabinet shuffle, Premier McGuinty withdrew from the Intergovernmental Affairs portfolio and became the province's first Minister of Research and Innovation.

Third year

On October 11, 2005, police raided the Sorbara Group offices — owned by Greg Sorbara and his brothers — as part of the ongoing Royal Group Technologies investigation. The warrant stated that there were reasonable grounds to believe Sorbara and other directors of Royal Group defrauded the company and shareholders when they bought land in Brampton, that was owned by a subsidiary of the Sorbara Group.^[30] Sorbara initially resisted opposition calls for him to step down, then resigned as Minister of Finance the same day. He consistently denied any knowledge of the specific allegations against him, and sued the RCMP to either clarify their case against him or withdraw their investigation. Following Sorbara's resignation, Dwight Duncan was appointed as Minister of Finance and Chair of the Management Board. Donna Cansfield took over Duncan's responsibility as Minister of Energy and Jim Bradley as Government House Leader.

The next day, the McGuinty government put forward a throne speech in October reiterating their priorities of health, education and economic prosperity. The speech outlined plans to offer the first money-back guarantee on a public service: a refund for people who do not receive a birth certificate within 15 days of applying on-line.

On November 18, 2005, it was announced that Ontario's Drive Clean emissions program was to be expanded rather than scrapped.

The 2006 budget was the third year of the four-year plan, and focused on the "infrastructure deficit". The centrepiece was MoveOntario, a $1.2 billion investment in transportation infrastructure. $400 million was invested to build and repair roads and bridges in municipalities across Ontario.

On May 18, 2006, a judge agreed with Greg Sorbara's contention that the Royal Canadian Mounted Police (RCPP) had erred in including his name in the search warrant. In striking Sorbara's name from the warrant, Justice Ian Nordheimer of the Ontario Superior Court said there were inadequate grounds for police to include him in the first place. The judge was particularly scathing in his review of the RCMP probe of Sorbara. On May 23, 2006, Sorbara was reinstated as Minister of Finance, while Duncan returned to the Energy portfolio.

On August 17, 2006, Foreign Direct Investment magazine (a British magazine owned by the Financial Times) named Dalton McGuinty "personality of the year" for encouraging investment in the auto sector, for developing a plan to increase energy production, and for promoting research and innovation.

Fourth year

On June 14, 2006, Energy Minister Dwight Duncan announced the McGuinty government's twenty-year electricity plan, which committed to spending $46 billion on rebuilding all of the province's ageing nuclear reactors. The plan also made the McGuinty government the first Ontario government since the 1970s to commit to building new nuclear stations, and further postponed the schedule for closing Ontario's coal stations to 2014. In response, Greenpeace activists occupied Energy Minister Duncan's offices.^[31] The day after the announcement of its long-term electricity plan The Globe and Mail published a front-page story that the government had quietly passed a regulation to 'exempt' its energy plan from an environmental assessment.^[32]

The government's decision to exempt the government's electricity plan was criticized by some environmental organizations. In a press release, Greenpeace, the David Suzuki Foundation, and the Pembina Institute noted that each had provided the government with a legal opinion prepared by the Canadian Environmental Law Association, which concluded that the government's energy plan would be subject to the province's Environmental Assessment Act.^[33]

The McGuinty government's 2007 budget was criticized by Toronto mayor David Miller, who argued that the province was refusing to "pay its bills", and said that Toronto's budgetary problems were the result of $500 million in social service costs mandated by the provincial government.^[34][35] During a later discussion, provincial Finance Minister Greg Sorbara declined to help the city to fix its $71 million shortfall, saying that "he doesn't have a mandate to fix this".^[36]

On July 26, 2007, McGuinty dismissed Mike Colle as Minister of Citizenship and Immigration following a report by the auditor general that Colle had mishandled government funds. He was criticized for giving out $32 million in government grants to immigrant and cultural groups without official applications or formal statements of purpose. In one case, the Ontario Cricket Association received $1 million when it asked for $150,000.^[37][38]

2007 re-election

In late 2004, John Tory was chosen to replace Ernie Eves as leader of the Progressive Conservative Party of Ontario. A principal secretary to former PC Premier Bill Davis, Tory was regarded as more moderate than Mike Harris and the mostly rural MPPs who made up the majority of his caucus. McGuinty's Liberals ran a candidate against Tory during the latter's successful bid to enter the legislature. Howard Hampton continued to lead the NDP. Though Tory out-polled McGuinty in the category of preferred premier, the Liberals held a lead over the Progressive Conservatives, while the NDP held around 20% support.

In October 2006, the McGuinty Liberals held their last Annual General Meeting before the 2007 election. The event set in place several key elements of their reelection strategy. First, American political consultant James Carville advised Liberal activists to stick to a simple message in the next election. Second, the party elected long-time activist Gord Pheneuf as the new president. Finally, Premier McGuinty laid out the theme of the next campaign: standing up for Ontario families.

On October 10, 2007, McGuinty and his Ontario Liberal Party won a consecutive majority government in the 39th general provincial election. The last Liberal Party Premier to achieve such success was Mitchell Hepburn during the 1930s.

Gas plant scandal

McGuinty's minority government was also criticized for a decision during the 2011 election campaign to scrap unpopular gas plants being constructed in Mississauga and Oakville — the move was seen as a politically expedient one made to improve the Liberal Party's chances of retaining the five ridings it held in the area, as the opposition PC's and NDP had already promised to scrap them. The opposition, emboldened by the minority government situation, demanded that Energy Minister Chris Bentley release all documents related to the decision. Bentley delayed prior to releasing 36,000 pages in September and insisted that all documents had been released. The cancellation of the gas plant was estimated to be $950 million to $1.1 billion over approximately 20 years. ^[45][46]

2011 re-election

On October 6, 2011, the Liberals were reelected for a third term in government, though they lost their majority in the Legislature. Only winning 53 of the 107 legislative seats, the Liberals were one seat short of a majority.

2012 prorogation and resignation

After it became known that there were an additional 20,000 documents Bentley was cited by a rare contempt motion by a legislative committee and was facing a contempt motion of the Legislature when McGuinty unexpectedly announced on October 15, 2012, that he was ending the legislative session by proroguing the legislature^[52] and that he would resign as premier as soon as the Liberal Party chose his successor, in January 2013.^[53][54]

Liberal House Leader John Milloy later stated that prorogation was necessary because an impasse was reached with labour leaders and the opposition over plans to freeze all public sector wages. The opposition charged that it was done to dodge negative publicity over the investigation and criminal probe into the Ornge Air affair, the controversial decision to halt construction of two gas-fired power plants during the previous election, and the subsequent threats by the opposition to vote on finding Cabinet ministers in Contempt of Parliament for withholding from the Legislature information related to halting the projects.^[55][56] In early 2013, Onley explained in an interview conducted by the Toronto Star that, though he and McGuinty discussed the matter, among others, before he granted the prorogation, he could only follow the constitution and adhere to the principles of responsible government; only if the premier were "trying to subvert democracy" could Onley have refused the advice and, as Onley put it, "something that's politically controversial doesn't fit that category. Doesn't even come close.... It's up to the politicians to work out the political process, the political decision-making that is behind prorogation—and the fallout after prorogation." On the subject of the lack of a date on which the Legislature would be summoned to return, the Lieutenant-Governor said he had no guide; the Legislature's standing orders outline that a specific date must be set, but the Legislative Assembly Act does not, and precedents are inconsistent.^[57]

While there had been speculation that McGuinty would become a candidate for the federal Liberal leadership election, on October 23, 2012, he announced that he would not be doing so.^[58] McGuinty resigned from his premiership on February 11, 2013.^[59] He resigned his seat in the legislature on June 12, 2013, at the end of the legislative session, after representing Ottawa South for 23 years.^[60]