Jeff Dean Leaves Google After 27 Years for AI Startup

One of the most influential engineers in Google's history is walking away, and he's taking three other senior AI researchers with him. Jeff Dean, Google's chief scientist and a co-founder of Google Brain, is leaving the company after 27 years to co-found Discovery Loop, a new AI startup focused on automating scientific and engineering research, according to CNBC's reporting on the departure. Alphabet shares fell roughly 4% following the announcement.

Dean joined Google in 1999 as employee number 30 and has been credited with some of the company's most important technical breakthroughs over nearly three decades, helping build the infrastructure that scaled Google from a startup into a company employing more than 190,000 people. "After an incredible 27-year run, Jeff Dean is at a moment where he wants to try something new, and we're excited to support him in that," CEO Sundar Pichai wrote in a memo posted to Google's blog.

Dean isn't leaving alone. Joining him at Discovery Loop are Sanjay Ghemawat, a Google senior fellow who wrote significant parts of Google's core computing and search infrastructure, Oriol Vinyals, a vice president at DeepMind and technical lead for Gemini, and Quoc Le, a co-founder of Google Brain and the key scientist behind AutoML-Zero, according to Quartz's reporting on the venture. That's a genuinely significant concentration of technical leadership departing simultaneously, all four having worked directly on both core Google systems and current frontier AI models.

Dean described Discovery Loop's core mission in concrete terms: "You propose an experiment, you implement what you need to run the experiment, you evaluate the experiment, and then you get results from that. Particularly in a lot of domains, you can fully computerize that whole loop." The company will initially focus on automating machine learning research and engineering before expanding into hardware design, drug discovery, and clean energy challenges, according to the Wall Street Journal, cited in Qz's reporting on the launch plan.

Notably, this isn't a clean break from Alphabet. Google will serve as a founding investor and cloud partner in Discovery Loop, a structured relationship that lets the company maintain a financial stake in Dean's new venture even as it loses his direct leadership, according to Qz's reporting on the deal. Radical Ventures and Khosla Ventures are co-leading Discovery Loop's seed round, which remains open, with the startup declining to disclose its valuation.

The departure is part of a broader AI leadership reshuffle at Google. Demis Hassabis, CEO of Google DeepMind, is stepping into a chairman role for that unit while also becoming chief scientist of parent company Alphabet, continuing to lead Isomorphic Labs, Alphabet's AI drug discovery spinoff, according to The Decoder's reporting on the reorganization. Koray Kavukcuoglu, DeepMind's chief technology officer, is being promoted to head of Google's overall AI division, a shift that connects directly to the intensifying frontier lab talent movement we covered in Google's Gemini 3.5 Pro delay and the researcher exodus that accompanied it earlier this year.

This departure and the accompanying leadership reshuffle is worth watching closely for any business currently evaluating Google's AI products and roadmap. The timing lands as Google navigates cash flow turning negative for the first time on record due to AI capital expenditure, while simultaneously racing to compete against OpenAI and Anthropic on frontier model capability and against Microsoft and Amazon on cloud infrastructure.

For businesses relying on Google Cloud or Gemini-based products, sustained leadership continuity at this scale is a genuine factor in long-term vendor confidence, and the coming months will show whether this reorganization accelerates Google's execution or introduces the kind of disruption that gives rivals room to pull further ahead.

Google chief scientist Jeff Dean is leaving after 27 years to co-found Discovery Loop, an AI startup focused on automating scientific and engineering research, taking three other senior Google AI researchers with him. Google will remain a founding investor and cloud partner in the new venture. The departure is part of a broader leadership reshuffle that also sees Demis Hassabis step down as Google DeepMind CEO to become Alphabet's chief scientist, with Alphabet shares falling roughly 4% on the news.