After majoring in history at Columbia University, brawny Brian Dennehy (born July 9, 1938) took a string of odd jobs to pay his way through Yale Drama School, and to afford private acting lessons. His first professional break came with the Broadway production Streamers. In films and TV from 1977, Dennehy is a most versatile actor, at home playing Western baddies (Silverado), ulcerated big-city cops (F/X), serial killers (John Wayne Gacy in the made-for-TV To Catch a Killer), by-the-book military types (General Groves in Day One, another TV movie), and vacillating politicos (Presumed Innocent). One of his most rewarding film assignments was as dying architectural genius Stourley Kracklite in Peter Greenaway's The Belly of an Architect (1987).

In addition to his many TV-movie roles (one of which, good-old-boy Chuck Munson in 1993's Foreign Affairs, won him a Cable Ace Award), Dennehy has starred in the weekly series Big Shamus, Little Shamus (1977), Star of the Family (1981), and Birdland (1994), as well as the sporadically produced Jack Reed feature-length mysteries. It was in one of the last-mentioned projects, Jack Reed: A Search for Justice (1994), that Dennehy made his directorial debut. Aside from his work in film and television, Dennehy has also had considerable success on the stage, particularly with his Tony-winning portrayal of Willy Loman in the 1998 Broadway revival of Death of a Salesman.

The actor continued to show his range in the 1995 comedy Tommy Boy (starring David Spade and the late comedian Chris Farley), in which he became well known for his role as Big Tom Callahan, and for a voice role in Ratatouille (2007) as Django, the father of rat and aspiring chef Remy.

Dennehy joined Robert DeNiro and Al Pacino in Righteous Kill, a 2008 police drama, and worked alongisde Russell Crowe in the 2010 suspense film The Next Three Days. In 2011, Dennehy played the pivotal role of Clarence Darrow in Alleged, a romantic drama set during the infamous Scopes Monkey Trial.