Google's Chief AI Scientist Jeff Dean Exits After 27 Years, Alphabet Shares Slide

Alphabet shares slid after The Wall Street Journal reported that Jeff Dean, one of Google's earliest employees and a key figure in its AI strategy (co-founder of Google Brain), is departing after nearly three decades to launch his own AI company. The exit raises fresh concerns about Google's ability to retain top researchers as competition for AI experts intensifies. 

Dean was Google's 30th employee in 1999 and will serve as CEO of Discovery Loop, a public-benefit corporation initially targeting machine-learning research and engineering. The startup will then transition to hardware design, drug discovery, and clean energy by automating multistep scientific experiments.

WSJ spoke with Dean:

"The four of us have been chatting about this a little bit and we got excited," Dean said in an interview at his Palo Alto, Calif., home Tuesday.

"We think by automating many of the classical experimental-loop aspects with machine learning models, augmenting human scientists and engineers, we'll be able to make it possible to explore more space in broad science areas to accelerate discovery."

The scientific process, he said, is about coming up with an idea for an experiment, setting up and running the experiment and then evaluating the results.

"Particularly in a lot of domains, you can fully computerize that whole loop," he said -- the inspiration for the startup's name.

Alphabet will invest in Dean's startup and provide cloud and computing capacity, while Radical Ventures and Khosla Ventures are co-leading a seed round. The valuation wasn't disclosed.

WSJ said that prominent Google researchers Oriol Vinyals, Quoc Le and Sanjay Ghemawat will be joining Dean in the new startup.

Shares of Alphabet dropped 5% after the report hit:

Four minutes after the WSJ report hit, Demis Hassabis, the head of Google DeepMind, wrote on X: 

I've been working towards AGI my whole life, and as we enter this pivotal moment, I'm stepping into a new role as Chair of Google DeepMind & Chief Scientist of Alphabet. This will allow me to focus on long-term strategy, and accelerating scientific breakthroughs, including leaning into my work at Isomorphic to help cure disease.

I’ve been working towards AGI my whole life, and as we enter this pivotal moment, I’m stepping into a new role as Chair of Google DeepMind & Chief Scientist of Alphabet. This will allow me to focus on long-term strategy, and accelerating scientific breakthroughs, including…

— Demis Hassabis (@demishassabis) August 5, 2026

Google CEO Sundar Pichai commented on the departures, saying Dean and Ghemawat helped engineer some of the company's most significant technology transitions over nearly three decades at the company and wished them the best.