Joon Sung Park is Co-Founder and CEO of Simile, an AI startup building high-fidelity digital twins to simulate and predict human behavior. He is a PhD student at Stanford University focused on human-computer interaction and natural language processing.

Joon completed his PhD research at Stanford under advisors Michael Bernstein and Percy Liang, pioneering the field of generative agents. His groundbreaking research on Generative Agents introduced AI systems that exhibit realistic human behavior and has been cited over 15,000 times.

Joon created the original concept of generative agents, which simulate believable human behavior using large language models with memory, reflection, and planning capabilities. His research has been featured in Nature, Science, The New York Times, and The Guardian, and he delivered a TED Talk on simulating human reality with AI.

Simile raised $100M in Series A funding led by Index Ventures, with participation from Bain Capital Ventures, A*, Hanabi Capital, and AI pioneers Fei-Fei Li and Andrej Karpathy. The company emerged from stealth in February 2026 after seven months of development.

Simile's technology helps companies like CVS predict customer behavior and business decisions by creating simulations with AI agents representing real people. The platform enables enterprises to anticipate market reactions, customer purchases, and strategic outcomes in minutes rather than months.