# Thinking Machines Co-founder Barrett Zoph Leaves OpenAI To Join Google > Source: > Published: 2026-08-27 06:18:10+00:00 AI researchers are changing camps at such a rapid rate it can be hard to keep track. The latest to switch jerseys is Barret Zoph, who spent the better part of the last two years bouncing between OpenAI and Mira Murati’s Thinking Machines Lab before landing, of all places, back at Google. Zoph announced on X that he is joining Google DeepMind as Vice President of Research, working on reinforcement learning and post-training, the same domain he built a reputation in during his OpenAI years. “Excited to announce I am joining Google DeepMind! I started my AI career in the Google Brain Residency class and am excited to rejoin. I am going to be working on RL and Post-Training – excited to announce more soon. Google has all the ingredients to continue to be incredibly successful in the AI space and am excited to be part of that mission,” Zoph wrote in his post. For Zoph, this is less a leap into the unknown and more a return to where he started. He began his career in the Google Brain Residency program back in 2016, where he spent years working on AutoML and neural architecture search, research that helped popularize the idea of using reinforcement learning to design neural networks rather than have humans hand-craft them. He stayed on through Google Brain’s merger into Google DeepMind, building a track record in large-scale model training before leaving in 2022 to join OpenAI as VP of Research for post-training, a period during which his team worked on alignment, tool use, evaluations, and the models that ultimately shipped inside ChatGPT. **A Turbulent Eighteen Months** Zoph’s résumé over the past year and a half reads like a case study in how unstable the upper ranks of AI labs have become. He left OpenAI in September 2024 alongside Mira Murati, when she stepped down as CTO, and became a co-founder and Chief Technology Officer at her new venture, [Thinking Machines Lab](https://officechai.com/ai/former-openai-cto-mira-murati-announces-new-startup-thinking-machines/). The startup raised roughly $2 billion from Andreessen Horowitz and others at a [valuation that reportedly touched $10 billion](https://officechai.com/ai/former-openai-cto-mira-muratis-new-startup-valued-at-10-billion-6-months-after-launch/) within months of launching, built almost entirely on the strength of the team Murati had assembled from OpenAI’s alumni network. That arrangement fell apart in January 2026. Murati announced she had [parted ways with Zoph](https://officechai.com/ai/thinking-machines-cto-barret-zoph-two-other-senior-researchers-rejoin-openai/), naming PyTorch co-creator Soumith Chintala as the new CTO. Within an hour, OpenAI’s Fidji Simo confirmed that Zoph, along with fellow Thinking Machines co-founders Luke Metz and Sam Schoenholz, would be returning to OpenAI. The Wall Street Journal later reported that an undisclosed workplace relationship had factored into Zoph’s exit from the startup, though neither he nor Thinking Machines has offered a detailed public account. Back at OpenAI, Zoph didn’t return to research. He was handed a very different mandate: leading the company’s push into enterprise AI sales, a role OpenAI framed as central to its plans to close the commercial gap with rivals ahead of an anticipated IPO. That stint lasted five months. By June 2026, Zoph had exited OpenAI for a second time, posting a goodbye note to staff on Slack. Google, evidently, had been waiting. **Thinking Machines’ Revolving Door** Zoph’s path also captures something bigger than one person’s career. Thinking Machines was founded in February 2025 with six co-founders, and that founding group has been shrinking almost since day one. [Andrew Tulloch was the first to go](https://officechai.com/ai/thinking-machines-cofounder-lillian-weng-quits-in-fourth-co-founder-exit/), leaving for Meta in October 2025 after reportedly turning down, and later accepting, a nine-figure pay package. Zoph and Luke Metz followed in January, both returning to OpenAI. Then in July, Lilian Weng, the company’s former VP of AI safety and one of its most visible co-founders, announced her own departure, citing months of health problems worsened by the pace of startup life. That left Murati as effectively the last woman standing among Thinking Machines’ original founders, a fact that [made](https://officechai.com/ai/amid-rapid-co-founder-departures-anthropic-is-the-only-major-ai-lab-with-all-its-co-founders-intact/) Anthropic something of an outlier for having kept its entire founding bench together. The irony is that all this churn hasn’t stopped Thinking Machines from shipping. The company released Tinker, its fine-tuning platform, launched a research preview of real-time “interaction models” that process audio and video natively, and in July put out [Inkling](https://officechai.com/ai/thinking-machines-inkling-becomes-top-us-open-model-on-artificial-analysis-intelligence-index/), a 975-billion-parameter open-weights model that quickly topped rankings for US-built open models. The product roadmap has moved forward even as the founding team around Murati has thinned out considerably. **Google’s Recruiting Spree** Zoph’s arrival also fits into a pattern of Google DeepMind aggressively pulling talent back into the fold this year, even as it has lost some of its own. Just weeks before Zoph’s announcement, Noam Shazeer, co-author of the original transformer paper and a DeepMind veteran Google had paid over $2 billion to reacquire via Character.ai, [left ](https://officechai.com/ai/google-ai-veteran-and-transformers-paper-coauthor-noam-shazeer-joins-openai/)for OpenAI. John Jumper, who shared the 2024 Nobel Prize in Chemistry for his work on AlphaFold, [announced](https://officechai.com/ai/nobel-prize-winner-john-jumper-leaves-google-deepmind-to-join-anthropic/) around the same time that he was headed to Anthropic. Set against that backdrop, landing a researcher back, and one with deep roots in Google’s own Brain Residency lineage, reads as a deliberate move to plug a gap opening up at the top of the company’s research bench. Where Zoph goes next in terms of actual output remains to be seen, since his post only teases “more soon” on the specifics. But for an industry where the same fifty or so names keep reshuffling across the same five companies, his move back to Google is really just the latest reminder of how fluid loyalty at the frontier of AI has become.