1978–1998: Software industry

Starting in his senior year at Stanford, McGregor worked for Xerox Corporation's Palo Alto Research Center (Xerox PARC). There, he joined a small software engineering team that helped create the windowing system for the Xerox Star—the first personal computer with a graphical user interface (instead of the text-based interfaces which preceded them).^[5] McGregor worked on the operating systems's windowing system (the "Cedar Viewers Window Systems"), the first system to display multiple programs at once.^[6]

In 1983, McGregor was recruited by Bill Gates to join Microsoft, to be the developer team lead for Windows 1.0—the company's first graphical user interface-based operating system.^[7] McGregor led the Interactive Systems Group, which began with a staff of three, characteristic of Microsoft's small development teams.^[5][8] In this role, the authors of a 1994 book said "his big-systems orientation" was seen as misaligned with the team's limited x86 PC environment, but described him as a "charismatic ideas guy" and an "articulate academic".^[9]

McGregor's first objective was to "figure out what Windows ought to be and deliver it to the world."^[9] At the time, Microsoft's proposed product didn't have a complete product specification.^[9] But in November 1983 McGregor flew with Gates and Steve Ballmer to New York's Plaza Hotel for a press event, where Windows was announced with support commitments from 23 computer manufacturers.^[9] In a later interview, McGregor said Microsoft "basically announced the product when we hadn't even designed it yet."^[5][9]

Gates' initial perspective, in 1983, had been that the development would be just a set of subroutines that individual applications would add to enable windowing; at the time, the product was going to be called "Interface Manager".^[9][5][10] But McGregor had written the window manager component for PARC's complete, interactive programming environment, and had called his PARC software "Windows". As the project grew in scope, it was McGregor's term that became the name for Microsoft Windows.^[10] The team grew as well, expanding to more than 30 members by the time they were fully staffed, making it Microsoft's single largest development group.^[5][9][8] At Microsoft during this time, Gates and McGregor interviewed every technical candidate.^[5]

After leaving Microsoft, McGregor joined Digital Equipment Corporation (DEC, now part of HP) as the Program Architect for DECwindows, where he was the co-author of the X Window System, Version 11 (also known as X11) in 1990 (the most current release as of 2020).^[11][12] He went on to lead DEC's Western Software Laboratory in Palo Alto, including the company's ULTRIX workstation software.^[11] In the mid-1990s, McGregor moved to Santa Cruz Operation, where he joined as the Senior Vice President of Products, and later became the company's Senior Vice President and General Manager.^[13]

1998–2016: Semiconductors

In 1998, McGregor was hired to lead Philips Semiconductors' Emerging Business unit, a newly-formed incubator where "promising technologies and products could be developed".^[14][15] The unit focused on rapidly growing markets such as networking, digital media, and RFID.^[16] By 2001, the unit had grown to nearly $1 billion in sales; that September, he was promoted to be President and CEO of Philips Semiconductors^[17][15][2] (now NXP Semiconductors)—one of Philips' five main divisions at the time, and the world's sixth-largest semiconductor company, with 35,000 employees.^[18][19] The unit had been unprofitable for several years; under McGregor, the unit became profitable.^[20] McGregor resigned from the role in late 2004 citing a wish to return to the U.S. for his children's school, after living abroad.^[19][21][22] Philips CEO Gerard Kleisterlee said of McGregor's departure, "We regret to see him leave. He has led the Semiconductors division through one of the most difficult periods in its history and managed to turn it around successfully into a leaner business with a strong focus on innovation."^[21]

In October 2004, it was announced that McGregor would be hired as the next President and CEO of chipmaker Broadcom, one of the biggest producers of the chips used in communications equipment.^[23][24][20] McGregor took over from an interim CEO as the company sought to refocus after the departure of its co-founder and former CEO Henry Nicholas, and soon a $2.24 billion stock options backdating scandal.^[24][14][19] In contrast with Nicholas, observers reported in 2006 that employees found McGregor "even-keeled", and said McGregor "prides himself on his organization".^[25] A 2011 interview called him both "amiable" and "brutally honest."^[8] During McGregor's tenure, Broadcom grew from $2.4 billion to $8.6 billion in revenue and became a Fortune 500 company; it first entered the list in 2009,^[26] and climbed to spot #327 in 2013.^[27]

In a 2014 interview, McGregor commented on the semiconductor industry's scale: "It has never before been possible to get an order for 100 million of something," he said. "It also means it costs $100 million or more to start a new chip company, which is why you see an industry roll-up and no venture capitalists funding new ones."^[28] He retired in 2016 upon completing Broadcom's $37 billion acquisition by Avago—part of a wave of acquisitions in the semiconductor industry,^[29] and, at the time, the largest acquisition of a technology company ever.^{[30][31][32][33]}