Starting this month, Stasior will lead an artificial intelligence group at Microsoft and will be reporting to Microsoft's chief technology officer, Kevin Scott.
A Ph.D. graduate in computer science from MIT, Stasior was head of Apple's Siri team for seven years, following the departure of Siri co-founders Adam Cheyer and Dag Kittlaus in 2012. Cheyer and Kittlaus had joined Apple when the company originally purchased Siri in 2010, but didn't stay long.
Stasior stepped down from his role as leader of Apple's voice assistant group in February, as part of a restructuring effort by John Giannandrea, Apple's senior vice president of machine learning and AI strategy.
Giannandrea was a prominent Google executive before being hired by Apple last year. With Giannandrea taking over the Siri team, Stasior was said to be stepping away from day-to-day management of Siri, yet remaining at the company. However, according to The Information, Stasior cut all ties with Apple in May.
Giannandrea's hiring came amid widespread criticism of Siri, which has shortcomings in comparison to AI offerings from the likes of Microsoft, Amazon, and Google. Apple made strides to improve Siri in 2018 under Giannandrea's leadership, with features like Siri Shortcuts in iOS 12.