Jakub Pachocki

Pachocki, a Polish computer scientist with a background in competitive programming and theoretical computer science, joined OpenAI and rose through its research organization, contributing to major training efforts including GPT-4 and the reasoning-focused o-series.

He was named chief scientist in May 2024 following Sutskever's departure, taking responsibility for OpenAI's core research direction. He has been closely associated with the development of test-time reasoning — the idea that letting models "think" longer at inference is a new axis of scaling.

As the scientific leader of the company that catalyzed the generative AI era, Pachocki's decisions on model architecture, training, and reasoning shape both OpenAI's roadmap and the broader research agenda that competitors track closely.