Tim Cook Reveals His Biggest Mistake and Apple’s Best Product Under His Leadership at Internal Event

Tim Cook has identified the iPhone 4S as his biggest mistake during his tenure as Apple CEO, citing the rushed integration of Siri as a flawed product launch.

Speaking at an internal Apple event, Cook reflected on the 2011 release of the iPhone 4S, which debuted alongside the voice assistant Siri. He described the feature as underdeveloped at launch, noting that it did not meet Apple’s usual standards for polish and reliability.

Cook contrasted this with what he considers Apple’s best product under his leadership: the transition to Apple Silicon. He emphasized that designing custom ARM-based processors for Macs was a decisive strategic move that redefined performance, efficiency, and product possibilities across the Mac lineup.

The shift to Apple Silicon began with the M1 chip in 2020, which delivered significant improvements in speed, battery life, and thermal management compared to Intel-based models. Cook noted that the change was not only about raw power but also enabled new capabilities in laptop and desktop design.

Under Cook’s leadership, Apple expanded into new product categories including the Apple Watch and AirPods. The Apple Watch evolved from an uncertain debut in 2015 into a widely adopted health and fitness device featuring ECG monitoring and blood oxygen tracking. AirPods, launched in 2016, became a cultural phenomenon and are regarded as Apple’s most successful accessory to date.

Cook acknowledged that while Apple did not produce a single breakthrough product on the scale of the original iPhone under his tenure, the company built multiple billion-dollar businesses and strengthened its ecosystem through sustained innovation rather than relying on one flagship release.

He also highlighted Apple’s financial growth during his leadership, noting that the company’s market capitalization increased from under $350 billion in 2011 to over $4 trillion by 2025, driven by diversified product lines and services revenue.

Cook is set to step down as CEO on September 1, 2026, after 15 years in the role. He will be succeeded by John Ternus, Apple’s senior vice president of hardware engineering, who has overseen hardware development including the Apple Silicon transition.