Bertrand Serlet

Bertrand Serlet is a French software engineer and entrepreneur, best known as the former Senior Vice President of Software Engineering at Apple and one of the key architects behind Mac OS X. 

Born on 19 December 1960 near Paris, France, Serlet studied at École normale supérieure Paris-Saclay, earning a master’s in mathematics, and later received a PhD in computer science from Université Paris-Sud / Université Paris-Saclay. 

He began his career as a researcher at INRIA, the French national research institute for computer science, before moving to the United States in the mid-1980s to work at Xerox PARC. In 1989 he joined NeXT, Steve Jobs’ company, where he worked on operating systems and development tools. 

When Apple acquired NeXT in 1997, Serlet followed Jobs to Apple. There he played a central role in defining and building Rhapsody, the NeXT-derived system that evolved into Mac OS X, and was widely considered one of the principal minds behind the platform. He became Apple’s Senior Vice President of Software Engineering in 2003, overseeing the development of multiple Mac OS X releases, with his influence particularly associated with OS X Snow Leopard’s focus on performance, refinement, and under-the-hood improvements. 

After 22 years at Apple, Serlet left the company in 2011, saying he wanted to “focus less on products and more on science.”  He went on to found or co-found several startups. In 2011 he co-founded Upthere, a cloud-storage and cloud-OS company later acquired by Western Digital.  In 2015 he co-founded Fungible, a data-center technology company focused on data-processing units (DPUs) for more efficient cloud infrastructure. 

Beyond his own companies, Serlet has served on boards and as an advisor and angel investor. He joined the board of Parallels, the virtualization software company, and has been an investor in deep-tech ventures, including photonics-based AI chip startup Arago, where he is cited as a former Apple VP and co-founder of Fungible. 

Across his career, Bertrand Serlet is often described as “the father of Mac OS X,” reflecting his long-term impact on modern operating systems and developer platforms, as well as his ongoing involvement in next-generation cloud and AI infrastructure.