Thomas Harrison joined the Agenus board in 2024 and has served as Lead Director since July 2025, chairing the Audit and Finance Committee and the Corporate Governance and Nominating Committee; the board has determined he qualifies as an audit committee financial expert. He is Senior Operating Partner at Merida Capital Partners.
He has been Chairman Emeritus of the Diversified Agency Services Division of Omnicom Group since 2016, having served as that division's Chairman and CEO from 1997 to 2016, overseeing marketing services businesses across public relations, crisis management, branding and healthcare advertising, and he earlier co-founded Harrison & Star Business Group, serving as its Chairman and CEO from 1987 to 1997. He holds Master of Science and Doctoral degrees from West Virginia University.