John Ternus officially takes over as Apple CEO today

Apple begins a new leadership era today, September 1, as John Ternus formally succeeds Tim Cook as chief executive. Apple announced the transition in April after its board unanimously approved the succession plan. Cook moves into the role of executive chairman and remains involved in areas including relationships with policymakers, while Ternus takes direct responsibility for the company heading into an unusually important mobile-product cycle.

His background is particularly relevant because he previously led Apple's hardware engineering organization and worked closely on products including the iPhone. The leadership change comes as Apple faces intensifying competition around artificial intelligence, pressure on App Store policies and increasing complexity across global supply chains. It also occurs immediately before the company's traditional September hardware season.

For the mobile ecosystem, the transition matters because decisions around iPhone design, silicon, services and developer economics ultimately affect billions of devices and transactions. Ternus inherits an extraordinarily profitable company, but also an industry moving faster around AI and new form factors than it has for several years.