Charles O'Neill

Charles O'Neill is Co-Head of Model Training at Baseten, a San Francisco-based AI infrastructure company, where he has worked since late 2025 following Baseten's acquisition of Parsed, a startup he co-founded to build specialized open-source language models. He is a General Sir John Monash Scholar and was an incoming DPhil candidate in Machine Learning at the University of Oxford under Professor Jakob Foerster, and previously a Tuckwell Scholar at the Australian National University. He is best known for his work on fine-tuning small open-source LLMs to outperform large closed-source models on specialized tasks, as well as research in mechanistic interpretability using sparse autoencoders.