Tom Lennox first appeared in the first episode of 24's 6th season, where he plays the White House Chief of Staff of President Wayne Palmer. He convinces Palmer to run for President prior to Day 6. Prior to serving as White House Chief of Staff, Lennox served as Policy Director on both Wayne and David Palmers' Presidential Campaigns. Thomas Lennox is a former member of the President's Foreign Intelligence Advisory Board.

He also serves on the boards of the Georgetown Institute, the James P. Williams Center for Public Affairs, and the Catalyn Foundation. He has published numerous articles and essays on topics including constitutional law, political philosophy, and public policy, and has co-edited several books. He has a Bachelor of Arts degree in political science from Yale University and a Phd.. in government from Harvard University