Tim Cook concluded his 15-year tenure as Apple's CEO on Monday, passing leadership to John Ternus, the head of the company's hardware division. The transition takes effect Tuesday, with Ternus, 51, expected to navigate a critical period for the tech giant.

Cook and Ternus have reportedly been closely collaborating in internal meetings leading up to the handover. Ternus will move into Cook's office at Apple's headquarters in Cupertino, California. His immediate priorities include overseeing the rollout of the company's latest product releases this fall, which are anticipated to feature Apple's first foldable iPhone and a long-awaited AI-powered update to its Siri voice assistant. Analysts are closely watching the public beta launch of Siri AI, emphasizing the need for a strong performance to maintain investor confidence.

Ternus will also be tasked with sustaining demand for core products such as MacBooks and iPads, despite recent price increases of up to $500 on some items. These price hikes are attributed to a global shortage of computer chips, which Apple has described as an "unprecedented challenge."

Despite these hurdles, Cook has expressed confidence in his successor, stating in April that Ternus is "without question the right person to lead Apple into the future." Cook, 65, was honored at a farewell event held Sunday at Apple's headquarters, featuring a performance by OneRepublic and attended by approximately 200 guests. Laurene Powell Jobs, the widow of Apple cofounder Steve Jobs, was among those who paid tribute to Cook. Ternus, along with Apple executives Eddy Cue and former COO Jeff Williams, also spoke at the event.

Cook, who publicly came out as gay in 2014, also delivered remarks at the gathering, acknowledging his partner, Mike, who was present. Although stepping down as CEO, Cook will transition to the role of executive chairman, where he will engage with policymakers globally. He also plans to spend more time at his vacation home in Palm Springs and pursue outdoor activities, while remaining involved with the company.

Tim Cook served as Apple CEO for 15 years.

During his 15-year leadership, Cook cultivated relationships with lawmakers from both major U.S. political parties and frequently attended White House events under both the Biden and Trump administrations. He also oversaw a significant expansion of Apple's business in China, navigating complex U.S.-China relations.

The leadership transition marks the end of a significant era for Apple. Under Cook's stewardship, the company's market capitalization surged from approximately $350 billion in 2011 to over $4.5 trillion. Cook shared a message on X on his last day as CEO, stating, "My title changes tomorrow, but the love I have for the Apple community never will. Thank you for being a constant source of inspiration. My gratitude is endless, and I’m excited for the next chapter!"

John Ternus officially becomes Apple CEO on Sept. 1.