The four-time Emmy winner will play Dempsey, a businessman with shadowy intentions who butts heads with President Martinez (Blair Underwood). Holbrook, 85, will make his first appearance on the conspiracy thriller on Oct. 11. The news was first reported by Entertainment Weekly.
Holbrook is best known for his series roles on Evening Shade and The Bold Ones and films including Into the Wild, which earned him an Oscar nomination in 2007. He most recently wrapped a recurring role on the new season of Sons of Anarchy.
The Event premieres Monday, Sept. 20 at 9/8c.