American actor best known for his role as the leader of the Counter Terrorist Unit (CTU) on TV's 24. He has guest starred in several popular shows such as Frasier, The X-Files, and The West Wing.
He started his career as a clown and wire walker in a circus.
He is also a published poet and yoga teacher.
He had a son named Seamus with Riad Galayini in 1999.
In 2016 he appeared on Castle, opposite Nathan Fillion.