Jeff Dean leaves Google after twenty-six years, Demis Hassabis moves to chair

After twenty-six years at Google, Jeff Dean is stepping down—not to retire but to launch a startup called Discovery Loop with three other senior researchers, Sanjay Ghemawat, Oriol Vinyals and Quoc Le. The departure is part of a leadership shake-up at the AI division that Sundar Pichai announced yesterday, which also includes a promotion for Demis Hassabis and a new appointment to head the unified division.

Demis Hassabis, founder of DeepMind and Nobel laureate, is leaving his role as CEO of Google DeepMind to become chair and chief scientist of Google. The day-to-day management will be taken over by Koray Kavukcuoglu, the chief AI architect who led the development of Gemini over the past year, and who will serve as senior vice president reporting directly to Pichai. Hassabis will step into Dean’s former position as chief scientist, a symbolic exchange given their shared history.

It is hard to overstate the four individuals’ imprint on Google’s infrastructure. Dean has presented a slide that reads like a modern internet history: Search, Google Ads, Gmail, the Mixture-of-Experts architecture that now powers large models, TPU chips, Google Translate, TensorFlow. Under their influence have passed figures such as Dario Amodei of Anthropic, Ilya Sutskever of SSI and OpenAI, and Noam Shazeer, who recently returned to OpenAI after a second stint at Google.

Discovery Loop is incorporated as a public benefit corporation, but has already closed a seed round with heavyweight funds Khosla Ventures, Radical Ventures, Lightspeed, Kleiner Perkins, and Google itself. Dean said the immediate tasks are to find office space and recruit an initial team. The stated mission is to automate the scientific research process.

The moves come against a backdrop of competitive pressure. At Google I/O 2026, a Gemini 3.6 Pro model was promised but has not yet arrived, while Anthropic has opened a gap in AI-generated code writing. That shortfall may have prompted Pichai to shift Hassabis into macro-level initiatives and hand the reins to Kavukcuoglu, who is already embedded in Gemini’s codebase. Dean is now starting at the stage every startup knows: searching for office space and assembling a core team, with a check open from several of the valley’s largest funds.