2014–2015

Cheika was appointed as the head coach of the Australia national team on 22 October 2014, with a three-year contract that would see him take the Wallabies through the 2015 Rugby World Cup.^[14]

Cheika took over after Ewen McKenzie's shock resignation the previous week and had very little time with the team before Australia started their 2014 end of year tour. His first match as coach was a non-capped game against the Barbarians, with the Wallabies winning 40–36.^[15] Cheika's first test match as coach was a 33–28 victory for Australia over Wales which was a record 10th consecutive win against them.

However, Cheika lost his first match against France a week later, with Australia being defeated 29–26. This for France was seen as revenge following Australia's dominant 3–0 series win over Les Bleus in June 2014 under former coach Ewen McKenzie. Cheika's team lost their next match against Ireland 26–23. Ireland had led 17–0 after just fifteen but three quick tries in the next fifteen minutes put Australia back in the game.

Australia then faced Rugby World Cup rivals England who had only win from their last six starts. England's forwards overpowered Australia in the match, however, to win 26–17. The result meant that Australia had lost three out of four test matches on their tour, their worst record since 2005. Cheika made it clear that the scrum needed to be fixed before the World Cup, and later sacked the forwards coach Andrew Blades.

Scrum coach Mario Ledesma was recruited to the Waratahs and began working on scrummaging with the Wallabies players that were in New South Wales.^[16] Brumbies head coach Stephen Larkham was brought in as backline and attack coach for the World Cup. Nathan Grey was appointed as defence coach.^[17]

In the lead up to the 2015 World Cup, Cheika is credited for inventing Giteau's law which enabled overseas based players to play for Australia.^[18]

During the 2015 Rugby Championship, Cheika made multiple changes to his side for each match despite the Wallabies' winning form. They opened their campaign with a 24–20 win over South Africa, winning in overtime with a late try from Tevita Kuridrani. They beat Argentina 34–9 a week later to set-up a decider with New Zealand in the final round. It was during that All Blacks match that Cheika started two specialized opensides for the first time since 2010, and they were both influential in the Wallabies 27–19 win. The win sealed the Rugby Championship for the Wallabies, their first ever Rugby Championship title, although including the former Trinations format it was the Wallabies fourth title since the competition began 1996. The Wallabies also achieved a 100% win rate for the first ever time in either format. However, the Wallabies failed to win the Bledisloe Cup, losing to New Zealand 41–13 in Auckland a week later.

Despite having only been in charge of the Wallabies for a year, Cheika led Australia to the 2015 Rugby World Cup final. They topped Pool A with victories over Fiji 28–13, Uruguay 65–3, England 33–13 and Wales 15–6. They narrowly beat Scotland in the quarter-final winning 35–34 after a controversial last minute penalty. They beat Argentina 29–15 in the semi-final to reach the final against the All Blacks. The Wallabies went down 16–3 at half time, but fought back in the second half to trail by only 21–17 with 10 minutes remaining. However a drop goal, penalty and a last minute try saw New Zealand claim an historic 34–17 victory. On 1 November, Cheika was named 2015 World Rugby Coach of the Year, becoming the first Australian coach to claim the title since Rod Macqueen in 2001, and the first non-New Zealander coach to win it since Ireland's Declan Kidney in 2009.

2016–2017

In 2016, England toured Australia for a three-test series, the first of its kind. The series saw Australia lose all three tests to be "whitewashed" for the first time in a home series since South Africa won 3–0 in 1971. The first test, lost 39–28, saw England win back-to-back tests on Australian soil for the first time since 2003, while winning at Brisbane for the first ever time. The 39 points scored against Australia were the most points Australia had ever conceded by an English team. The second test saw England win 23–7, a record winning margin on Australian soil and a record third consecutive away win, to see England claim their first ever series win over Australia. The final test saw an accumulative score of 84 points, with England the victors 44–40.

He led Australia to second in the 2016 Rugby Championship despite losing the first two matches on an aggregate score of 71–17 against New Zealand. Cheika lead the Wallabies to their first win of the season against South Africa in round 3, winning 23–17, before defeating Argentina the following week 36–20. Australia narrowly missed out on their first ever victory at Loftus Versfeld Stadium, losing to South Africa in Pretoria 18–10. In the final week of the Championship, Argentina hosted Australia in London, where the teams became the first to play a Rugby Championship or Tri-Nations match outside any of the SANZAAR nations. Australia were the victors, 33–21. In the final Bledisloe Cup on 22 October, Australia were defeated 37–10, conceding 18 points in the closing 20 minutes. Australia's 2016 Spring tour saw mixed results, convincingly defeating Wales 32–8 in the opening week, before narrowly defeating Scotland with a 74th minute try by Tevita Kuridrani to win 23–22. Their third game saw Cheika completely change the team for the French clash, but still managed to claim the victory 25–23. The fourth and fifths matches on the tour saw the Wallabies lose their eight and ninth tests of the year, losing to Ireland 27–24 and England 37–21, with Ireland loss killing the Australian's chances of claiming a successful Grand Slam tour.

Australia's 2017 season started with a 37–14 victory over Fiji where Cheika gave four players their international debut. The following week, Australia lost to Scotland for the first ever time in Sydney, losing 24–19. It was the first time ever Australia had lost to Scotland twice in row at home, with the last loss, 9–6 in 2012, the last time Scotland had beaten Australia. Australia's final June test was a 40–27 victory over Italy, though for most of the game the teams weren't separated by many points with the score being 28–27 until the 75th minute. During the 2017 Rugby Championship, Cheika was heavily criticized for his constant changing off match day teams. It wasn't until the last round of the Championship that Cheika retained the previous starting XV in two consecutive matches, for the first time in his Career as Wallabies head coach. The Championship started with a 54–34 hammering to New Zealand, conceding 8 tries in 47 minutes. At the 50 minute mark, the score was 54–6, however Australia clawed back the margin scoring four tries in the last quarter of the game. The return fixture the following, Australia came within minutes of claiming an away victory to New Zealand, leading the All Blacks 29–28 at the 77th minute mark. However a Beauden Barrett try on the 78th minute, saw New Zealand claim a 35–29 victory, despite at one point being behind 17–0 down early on in the game. The third round saw Australia and South Africa draw for the first time since 2001, after the game ended 23–23. The result was repeated in the reverse fixture three weeks later, when it ended 27–27. Australia ended on a high, putting a solid performance against Argentina away, running out victors 37–20.

Ahead of the Wallabies Spring tour, Cheika led Australia to a 23–18 victory over the All Blacks in the third Bledisloe Cup. It was the first time since 2015 that the Wallabies had defeated the world champions. This win was backed up by a narrow 31–28 non-test victory over the Barbarians and a week later a 63–30 win over Japan in Yokohama, in what was both experimental sides for Australia. Australia's first major test on their Spring tour came on 11 November, where they faced and defeated Wales, 29–21. Despite the score being 13–6 heading into the final 10 minutes in the England test, Australia went on to lose their first tour match 30–6, conceding 3 tries. Australia's final test was a record defeat at the hands of Scotland, losing 53–24 in Edinburgh for the first time since 2009.

2018–2019

The Wallabies endured a shocking run in 2018; in June, Cheika led the team to a series defeat against Ireland, losing 2–1 having won the first test 18–9. However, a first loss to Ireland at home since 1979 in the second test (26–21) followed by a close encounter in the third test (16–20), meant Ireland claimed a first ever series win over Australia. Despite losing the series, the Wallabies out scored their opposition in terms of tries, scoring 6 tries to 3. It was also a first for Cheika in the second test, naming an unchanged matchday 23 for two consecutive tests, retaining the same team from the first test.^[19]

During the 2018 Rugby Championship, Cheika faced severe criticism over the team's form and a string of poor results. His job was openly questioned in the Australian media after the team won only two games during the Championship. Despite leading New Zealand 6–5 in the opening match, the Wallabies went onto lose the match 38–13, and despite being marginally behind the All Blacks in the second test, 7–14 at half time, they also went on to lose that match 40–12. Cheika's side did manage an impressive 23–18 victory over South Africa to retain the Mandela Challenge Plate. However, the following week, Australia lost to Argentina 23–19, which was the first time since 1983 that Argentina had beaten Australia on home soil. This meant the Wallabies dropped to a record low seventh place on the World Rugby Rankings and, after Round 5, their woes continued as they lost to South Africa 23–12. In the final round, Argentina led Australia 31–7 at half time in Salta. However a record come-back in the second half meant Cheika and his team won 45–34, to secure third place in the Championship. In the third Bledisloe Cup match, held in Japan, the Wallabies put on a better performance but failed to capitalise on their chances, seeing the All Blacks win 37–20.

Cheika's team endured a similarly dismal run in the 2018 autumn internationals, losing 9–6 to Wales (their first win over Australia since 2008) before salvaging a consolation 26–7 victory against Italy. The Wallabies ended 2018 with a sixth consecutive defeat to England, going down 37–18. The team's win–loss record, having won only four out of thirteen test matches, was their worst since 1958. A review of the team's performance was conducted by the administration of Rugby Australia, with the board electing to back Cheika through to the 2019 World Cup. The decision was widely derided in the Australian sporting press, with speculation rife that the administration were unable to afford to terminate Cheika's contract.^[20]

2019 saw much change in the Australian set-up, beginning with the sacking of Stephen Larkham as attack coach and the introduction of a selection panel made up of Cheika, newly selected Director of Rugby Scott Johnson and Michael O'Connor who acts as an independent away from the national team coaching team. The new process started with a 35–17 loss to South Africa in the opening round of the 2019 Rugby Championship. The following week, Australia gained just their first win of the Championship, defeating Argentina 16–10. However it was the final match against New Zealand that proved a success, after winning 47–26, a joint record defeat for the All Blacks; through this result meant a win in the second Bledisloe Cup match meant Australia would reclaim the title for the first time since 2002. However, the Wallabies lost 36–0 to see the trophy remain in New Zealand.

At the 2019 Rugby World Cup Australia won three of their four pool matches but a close loss to Wales led to a quarter-final fixture with England. A defeat by 40–16 in that match ended the Australian campaign and the following day Cheika announced that he would resign as head coach by the end of the year.^[21] His contract had been due to expire following the World Cup.^[22]

2022–2023

In March 2022 it was confirmed that Cheika would coach the Argentina national rugby union team from 2022 through to the 2023 Rugby World Cup,^[25][26] with assistant coach Felipe Contepomi taking over post-World Cup.^[27][28]

Cheika's first matches as coach came against Scotland in a three-test home series. Starting half-back Tomás Cubelli was ruled out of the series due to injury acquired in training, while starting fly-half Nicolás Sánchez was replaced in game one after twenty-one minutes of play (calf tear).^[29] Argentina won the first game (26–18) in a tight back-and-forth match in San Salvador de Jujuy.^[30] Although the first test was a close win for Argentina, the second was a dominant blowout win for Scotland (6–29), scoring four tries to zero. Scotland also kept Argentina scoreless in the second-half, levelling the series 1–1.^[31][32] Scotland also levelled the overall record between the two sides (10–10). In the third and final test, the decider, Argentina clawed back a fifteen-point deficit to win the match in a spectacular last-minute final play in Santiago del Estero (34–31), winning the series 2–1.^[33][34] It was Cheika's fourth win in total against Scotland out of seven matches.

In their first two tests of the 2022 Rugby Championship, Argentina played Australia at home, following SANZAAR's change to the Rugby Championship round-robin format, which will see some teams play two home matches, two away matches and two home-and-away matches against the three other teams of SANZAAR.^[35] In round one Argentina lost 26–41 at Estadio Malvinas Argentinas, Mendoza after leading 19–10 at half-time.^[36][37] In round two Argentina played Australia at Estadio San Juan del Bicentenario, San Juan. Similar to their first round encounter, Los Pumas started the match in a rapid fashion, scoring four tries in just a half-hour of play, and lead Australia by sixteen points at half-time (26–10).^[38] After Wallaby flanker Fraser McReight was yellow carded in the sixty-third minute, Argentina prop Thomas Gallo went over for his second try of the match, extending their lead out to the biggest margin of the match up to that point: twenty-one points (31–10).^[38] A snappy reply from Australia's Len Ikitau saw them reduce the lead back to fourteen-points by the seventieth minute with only fourteen players on the field.^[38] However, in the final three minutes of the match, Argentina scored two unanswered tries finishing the match with their biggest victory of Australia (48–17; thirty-one points),^[38][39][40] beating their previous best victorious margin of fifteen points in 1983. After the match, Cheika stated: “I love these guys, they’re my crew now[.]” adding, “I was up on the last try, cheering. But then I started crying because I know I probably shouldn’t be doing this. It was a bit confusing for me, personally.” [...] “But they’re my boys now. That’s my team. I will do everything I can to help them get success and enjoy rugby. They are paying me a lot of respect here and people are believing in the things that we are doing. I have to do everything I can to help them.”^[41][42]

Following Argentina's first two rounds at home, rounds three and round four were played away against New Zealand, the first test at Rugby League Park, Christchurch, the second at Waikato Stadium, Hamilton. Argentina scored the first points of the game via a penalty goal through Emiliano Boffelli in the seventh minute.^[43][44] After ten minutes of play, and conceding a try, Boffelli scored another penalty goal for Argentina in the seventeenth minute.^[43] Following Argentina's second penalty goal, New Zealand scored a converted try and two penalty goals to lead 15–6, before Boffelli kicked another two penalty goals before half-time, reducing the deficit to three points (15–12).^[43][44] Argentina made the strong start to the second-half, capitalising on a re-start after a penalty goal Richie Mo'unga.^[43] Flanker Juan Martín González received the ball before he ran around into space on the short side of the field, going through for a try.^[43][44] Boffelli slotted the conversion, and, for the third time in the match, Argentina were leading. With vast bursts of physicality and many mistakes throughout the second-half, Boffelli added another six points to the score before full-time.^[43][44] The match finished New Zealand 18, Argentina 25.^[45][46] Historically, it was the first Argentina win against New Zealand, in New Zealand. It was the first time ever that New Zealand had lost three-straight home matches (the first two were against Ireland).^[47][48] It is also the second, back-to-back history-making match for Argentina with Michael Cheika as coach, mentioning, “It’s a first for me, I’ve never won a Test match in New Zealand.” When asked about the matches specialty regarding beating his home country (Australia) vs. beating New Zealand, Cheika replied: “I don’t look at it like that. I look at it from our point of view and growing the team and, in particular, towards the World Cup.”^[49] Following the historic result, Argentina jumped two placings in the World Rugby Rankings (9th to 7th)^[50] to sit just 0.01 points below Australia in sixth.^[51][52]

In the following round (four), Argentina suffered there heaviest defeat to New Zealand since 1997, losing 53–3.^[53][54] In very wet conditions, it took Argentina thirty-two minutes of play to finally score any points, coming through the boot of Emiliano Boffelli,^[55] by which point they had already conceded two tries and a penalty goal (score reading 17–3).^[55] Conceding over double the amount of turnovers as New Zealand, Argentina went on scoreless while the All Blacks scored an additional five tries by the end of the match.^[55] The loss to New Zealand put Argentina last on the Rugby Championship table,^[56] having been first for the previous two rounds (13 August – 3 September 2022).^[57][58] Despite the heavy defeat, Argentina went up one ranking (7th to 6th),^[59][60] due to Australia (whom was in sixth, one placing above Argentina) losing at home to South Africa by more than fifteen points in the same round.^[61]

In the same month (September 2022), former Australia scrum-half under Michael Cheika, Will Genia, said he could see the return of Cheika coaching Australia.^[62] Genia told Fox Sports Australia, “I can see it [Cheika returning as coach of Australia] and I would love to see it because I know he still harbours aspirations for it,” adding: “He loves coaching”.^[62]