On Monday afternoon, Apple announced that Tim Cook will resign as CEO, a position he has occupied since 2011, when he took over from the late Steve Jobs. Starting September 1 this year, Senior Vice President of Hardware Engineering John Ternus will assume the top executive role.

Cook will continue with the company as executive chairman, and Ternus will become a member of Apple’s board of directors. Arthur Levinson, who has been Apple’s non-executive chairman for the last 15 years, will take on the role of lead independent director, also effective September 1.

This shift has been anticipated for some time and concludes one of the longest and most significant tenures a CEO has had at any firm. Cook took charge during a period of considerable uncertainty — Jobs passed away from pancreatic cancer just six weeks after formally transferring the role — and inherited a company that numerous industry observers and fans found challenging to distinguish from its legendary founder. What he departs with is a $4 trillion enterprise, boasting annual revenues that have increased more than fourfold during his leadership.

“Being the CEO of Apple has been the greatest honor of my life,” Cook expressed in a statement on Monday. “I cherish Apple deeply, and I am profoundly thankful to have collaborated with a team of such brilliant, innovative, creative, and caring individuals who have consistently demonstrated dedication to enhancing the lives of our customers.”

When Cook arrived in Cupertino in 1998, he was not brought on as a visionary. Instead, Jobs, who had recently returned to Apple after a lengthy absence, required someone to rectify a supply chain that was, by most evaluations, a mess. Cook, originally from Mobile, Alabama, who worked for 12 years at IBM before joining Intelligent Electronics and Compaq, accomplished what was necessary and more. He rapidly closed warehouses and consolidated suppliers and has been widely recognized for transforming Apple’s manufacturing processes into a competitive strength over time instead of a drawback.

His elevation to CEO was never guaranteed.

For years, it was thought in and around Silicon Valley that no one could succeed Jobs. It was difficult to envision someone more unlike the charismatic product innovator than Cook, a methodical expert in supply chain and operations. However, when Jobs’ health necessitated him to withdraw multiple times — in 2004, 2009, and again in 2011 — Cook managed the company sufficiently well that when Jobs formally bequeathed him the title, he was the clear choice.

There were, of course, notable missteps afterwards. Among the most prominent was Apple Vision Pro, the mixed-reality headset that Cook promoted as the company’s next significant platform and that was mainly disregarded by consumers unwilling to invest several thousand dollars to wear a computer that weighs over a pound on their face.

Nonetheless, his term has been tremendously successful by various other standards. As the company highlighted in its own announcement on Monday regarding the executive transition, Cook transformed Apple Services into a business surpassing $100 billion yearly. Apple also attributes the thriving wearables division to him. (Last year, the Apple Watch represented an estimated 25% of global smartwatch sales.)

Levinson, representing the board, praised Cook’s leadership as “unparalleled and exceptional,” stating that Cook’s “integrity and values are embedded in everything Apple undertakes.” Levinson remarked that the board is “excited” Cook will remain as executive chairman.

Ternus, who at 51 is approximately the same age Cook was upon becoming CEO, has dedicated nearly his entire career to Apple. A native of California, he pursued mechanical engineering at the University of Pennsylvania, participated on the varsity swim team, and graduated in 1997. After a short period designing virtual-reality headsets at a small company called Virtual Research Systems, he joined Apple’s product design team in 2001. By 2013, he held the title of vice president of hardware engineering. In 2021, when his predecessor Dan Riccio stepped aside to manage what would ultimately become the (ill-fated) Vision Pro, Ternus was elevated to senior vice president, making him the youngest member of Apple’s executive team.

Unsurprisingly, Ternus has had a hand in much of what Apple has launched over the past decade. According to Apple, he played a crucial role in the debut of iPad and AirPods and has supervised numerous iterations of the iPhone, Mac, and Apple Watch. His team’s contributions became increasingly visible this past fall with the unveiling of a new iPhone lineup that included the iPhone 17 Pro and Pro Max, the iPhone Air, and the iPhone 17 itself.

On the Mac front, Ternus has contributed to strengthening the category, including through the recent introduction of the more economical MacBook Neo. His team also played a role (according to Apple) in advancing AirPods to the point where they now serve not just as headphones but also as an over-the-counter hearing health system.

Beyond the products, Ternus has focused heavily on durability and repairability. Apple credits him for introducing new materials and manufacturing practices that have lowered the carbon footprint of Apple’s products, including a new recycled aluminum compound employed across various product lines, while also extending the longevity of several Apple devices through improvements in their reparability.

In his own statement on Monday, Ternus remarked: “Having spent nearly my entire career at Apple, I have been fortunate to work under Steve Jobs and have Tim Cook as my mentor,” he stated. “I am honored to take on this role, and I pledge to lead with the principles and vision that have defined this extraordinary organization for half a century.”

Cook expressed of Ternus: “John Ternus possesses the mind of an engineer, the spirit of an innovator, and the heart to lead with integrity and honor,” he stated. “He is undoubtedly the right individual to guide Apple into the future.”