Apple is set for a major leadership shift on Monday as John Ternus assumes the role of chief executive officer, replacing Tim Cook who will transition to executive chairman of the board.

The company announced the planned change on April 20, following a long-term succession process approved unanimously by the board. Ternus, currently senior vice president of hardware engineering, has spent 25 years at Apple and will join the board effective with his new position.

Cook, who has led Apple since 2011 after succeeding Steve Jobs, will continue as CEO through the summer to ensure a smooth handover. In his new capacity, Cook will assist with select matters including engagement with policymakers worldwide. Arthur Levinson, the non-executive chairman for the past 15 years, will become lead independent director.

Ternus, 51, rose through the ranks after joining the product design team in 2001. He advanced to oversee hardware engineering for major product lines including the iPhone, iPad, Mac, and AirPods, and played a key role in Apple's shift to custom silicon chips. Colleagues and analysts have praised his engineering focus and attention to detail.

Under Cook's tenure, Apple grew its market value significantly and expanded into services and new hardware categories such as the Apple Watch and Vision Pro. The company now faces challenges in artificial intelligence integration and upcoming product launches, including a foldable iPhone expected this fall.

Ternus has stated he is humbled by the opportunity and committed to upholding the company's values. The transition maintains continuity with an internal candidate experienced in Apple's core operations.

Johny Srouji, previously senior vice president of hardware technologies, has been named chief hardware officer to handle engineering responsibilities previously under Ternus.