After 15 years, Tim Cook is set to step down as Apple CEO, passing the role to John Ternus, the company’s senior vice president of hardware engineering. Beginning September 1, Ternus will take charge of one of the world’s most valuable companies.

Ternus has spent nearly half his life at Apple. At 51, he has been with the company for 25 years.

He joined Apple’s product design team in 2001, making it only his second job after college—his first was at a small virtual-reality company, Virtual Research Systems.

By 2013, he had risen to vice president of hardware engineering, and in 2021 he was promoted to senior vice president.

Fifteen years younger than Cook, Ternus was one of the youngest senior Apple executives previously tipped as a potential successor, suggesting the company may be preparing for long-term leadership stability.

Apple, after all, has had only two CEOs this century, underscoring its emphasis on continuity at the top.

Ternus reports directly to Cook, whom he regards as a mentor, and oversees all of Apple’s hardware engineering, a significant role at a company defined by flagship devices like the iPhone and MacBook.

In a 2024 commencement address at his alma mater, the University of Pennsylvania’s School of Engineering, Ternus reflected on his time at Apple and the lessons he has learned there, offering a glimpse, albeit a polished one—into his character and leadership style.

“Always assume you’re as smart as anyone else in the room, but never assume that you know as much as they do,” Ternus said in the speech. “With this mindset, you’ll find the confidence you need to push forward, but more importantly, the humility to ask questions.”

As CEO, Ternus will face the challenge of helping Apple catch up in the AI race, while also deciding how to further develop the core technology behind the Vision Pro.