Tim Cook’s 15-Year Run as Apple CEO Comes to an End

Tim Cook’s 15-year tenure as Apple’s chief executive officially comes to an end on August 31, 2026, marking one of the biggest leadership transitions in the company’s history. Cook became CEO in 2011 after Steve Jobs stepped down, and he leaves behind an Apple that is dramatically larger in revenue, market value and global reach. Apple says Cook will become executive chairman, while John Ternus takes over as CEO on September 1.

Under Cook, Apple’s market capitalization expanded from roughly $350 billion to around $4 trillion, while annual revenue grew from about $108 billion in 2011 to more than $416 billion in 2025. Apple also expanded its ecosystem with products including the Apple Watch, AirPods and Vision Pro, while services such as Apple Music, Apple TV, Apple Pay and iCloud became increasingly important to the company.

Cook’s biggest strength was arguably operational execution. His supply-chain expertise helped Apple scale production and maintain its enormous global hardware business. During his tenure, Apple shipped more than 3 billion iPhones, while the number of active Apple devices worldwide surpassed 2.5 billion. The company also developed its own Apple Silicon chips, helping strengthen its control over hardware and software while improving performance and efficiency.

However, Cook leaves at a complicated moment. Apple remains enormously profitable, but the company faces increasing pressure in artificial intelligence, regulatory challenges and continued dependence on manufacturing in China. Apple has increasingly worked with external technology partners on AI, while competitors such as OpenAI and Google have moved aggressively in generative AI. The next CEO will therefore inherit a highly successful company but one that needs to demonstrate that it can remain at the forefront of the next technological wave.

That challenge now belongs to John Ternus, Apple’s longtime hardware engineering chief. Ternus officially becomes CEO on September 1, with his first major test arriving almost immediately: Apple’s September 9 product event, where the company is expected to unveil its next iPhone generation and potentially its first foldable iPhone. Cook’s era was defined by scale and operational excellence; Ternus now has to determine whether Apple can combine those strengths with a new era of AI-driven innovation.