Apple’s head of artificial intelligence, John Giannandrea, announced his resignation on Monday. This move comes as the company works to get its AI-powered Siri back on track following delays in launching the updated assistant earlier this year.

Amar Subramanya has been appointed Apple’s new Vice President of Artificial Intelligence. Subramanya spent 16 years at Google before joining Microsoft’s AI division in July as Corporate Vice President of Enterprise AI. At Apple, he will oversee the development of the company’s AI models, machine learning research, and AI safety initiatives.

Giannandrea previously led AI and search efforts at Google before joining Apple in 2018 to help enhance the company’s voice assistant.

In March, Apple postponed the release of a more personalized version of Siri, acknowledging it was taking “longer than we anticipated.” According to Bloomberg, CEO Tim Cook had “lost confidence” in Giannandrea’s ability to lead Apple’s AI team, prompting the appointment of Vision Pro chief Mike Rockwell to take over AI oversight. Giannandrea will remain with Apple as an advisor until his retirement in spring 2026.

Apple stated that Subramanya’s experience in integrating AI research into real-world products “will be critical to Apple’s ongoing innovation and future Apple Intelligence capabilities.” As part of this leadership shift, Subramanya will report directly to Craig Federighi, Apple’s Senior Vice President of Software Engineering. The company plans to unveil an upgraded Siri next spring, with Bloomberg reporting that some of the assistant’s new features will be powered by a customized version of Google’s Gemini AI model.

In a statement, Cook said, “Artificial intelligence has long been central to Apple’s strategy, and we’re thrilled to welcome Amar to Craig’s leadership team and bring his exceptional AI expertise to Apple. Alongside Amar’s arrival, Craig’s leadership team—and its AI responsibilities—continues to grow. He has played a pivotal role in advancing our AI efforts, including overseeing the work to deliver a more personalized Siri to users next year.”