Noam Shazeer

Mathematics, then Google

Shazeer studied mathematics and computer science at Duke University before joining Google in 2000. His name sits on a run of papers from the company's labs. They include the sparsely-gated mixture-of-experts layer and Mesh-TensorFlow, both from the Transformer's era.45910

T5, the text-to-text transfer-learning paper, followed in 2019, and LaMDA, a language model built for dialogue, in January 2022. OpenAlex counts 56 works and 40,322 citations in the matching author record, with an h-index of 31.111217

Leaving to put the technology in front of billions

Shazeer and Daniel De Freitas left Google to build their own large language model. Character.AI was introduced publicly in December 2022. Shazeer told TIME why he went: "I left Google to follow the spirit of entrepreneurship, and to work on the hardest problems in the world rather than just working on small features within a much larger company."3614

He also gave a practical reason: "The next step for me was doing my best to get that technology out there to billions of users. That's why I decided to leave Google for a startup, which can move faster." On what people would do with it, he said "We believe the best use cases are things we haven't thought of yet."14

Two billion messages in five months

By March 2023 the company had announced a Series A led by a16z and a preview of its C1.2 model. It said users had sent more than 2 billion messages in the five months since launch.13

TIME described the site as one that lets you talk to AI versions of famous people, real and fictional. Later reports put the Series A at $150 million, at a $1 billion valuation.714

Back to Google, and onto Gemini

In August 2024 Axios reported that Shazeer and De Freitas would rejoin Google. The Information reported that Shazeer would be co-technical lead on Gemini. His GitHub profile now reads: "Currently Co-Tech-Lead on Gemini."127

Lawsuits and inquiries at Character.AI

Shazeer is named personally in Garcia v Character Technologies, No. 6:24-cv-01903, which also named Character Technologies and Google. In July 2025 a federal judge denied his motion to dismiss and allowed jurisdictional discovery, which is a procedural ruling, not a finding on the claims. The AP reported in January 2026 that Google and Character Technologies had agreed to settle, with terms undisclosed and court approval still needed.1516

The company has also faced regulators. Texas opened an investigation into Character.AI and fourteen other companies in December 2024 over minors' privacy and safety, and Character.AI said it took user safety very seriously. The FTC sent information orders in September 2025 as part of a study with no specific law-enforcement purpose, and Character.AI said it would collaborate.18192223

In 2026 Pennsylvania sued Character Technologies, alleging its chatbots held themselves out as licensed doctors. Character.AI said it prioritises responsible product development and the well-being of its users.24

Shazeer, year by year

1. 2000

   Joined Google5

2. 2017

   Co-authored Attention Is All You Need, and the sparsely-gated mixture-of-experts paper49

3. 2018

   Co-authored Mesh-TensorFlow: Deep Learning for Supercomputers10

4. 2019

   Co-authored the T5 text-to-text transfer-learning paper11

5. Jan 2022

   Co-authored LaMDA: Language Models for Dialog Applications12

6. Dec 2022

   Character.AI was introduced publicly by Shazeer, Daniel de Freitas and the Character team3

7. Mar 2023

   Character.AI announced a Series A led by a16z and a preview of its C1.2 model, and said users had sent more than 2 billion messages in five months13

8. Sep 2023

   TIME named him in its list of influential people in AI, as CEO and co-founder of Character.AI14

9. Aug 2024

   Rejoined Google as part of Google's deal with Character.AI7

10. Aug 2024

    The Information reported he would be co-technical lead on Gemini2

11. Jul 2025

    A federal judge denied Shazeer's motion to dismiss in Garcia v Character Technologies, allowing jurisdictional discovery15

12. Jan 2026

    Garcia v Character Technologies was reported as settled; terms were not disclosed16

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