Born in Bridgeport, Connecticut

Raised in Brooklyn, New York

Served with the Marine Corps

Returned home with a concussion and shrapnel wounds

Worked as a meat truck driver, bartender, and a salesman

Professional stage debut in Chekhov's "Ivanov"

New York stage debut in "Streamers"

Film acting debut in "Semi-Tough"

TV-movie debut, "It Happened at Lakewood Manor/Panic at Lakewood Manor/Ants!"

Starred as Arnie Sutter in first TV series, the short-lived CBS detective drama, "Big Shamus, Little Shamus"

Starred as Leslie "Buddie" Krebs in the short-lived ABC family sitcom, "Star of the Family"

Appeared with William Hurt in "Gorky Park"; Hurt told him he had too much talent to be so casual about acting

Appeared onstage in Chicago in "Galileo"

First feature lead, as co-star of, "F/X"

Portrayed notorious serial killer John Wayne Gacy in the syndicated two-part TV-movie, "To Catch a Killer"

Made producing debut as co-executive producer of the TV-movie, "Jack Reed: Badge of Honor", in which he also starred

Starred as hospital psychiatrist Dr. Brian McKenzie in the short-lived ABC medical drama, "Birdland"

Made directorial debut with "Jack Reed: A Search for Justice"; also scripted and acted in

Had recurring role as David Spade's father on the NBC sitcom "Just Shoot Me"

Starred in Chicago production of "Death of a Salesman"; production transferred to Broadway in February 1999 earning Dennehy some of the best notices of his career

Portrayed Louis Bromfield in the CBS biographical miniseries "Too Rich: The Secret Life of Doris Duke"

Reprised role of Willy Loman in Showtime adaptation of "Death of a Salesman"; earned Emmy nomination

Hosted "Arrest & Trial", a syndicated reality TV series produced by Dick Wolf

Headlined the NBC sitcom "The Fighting Fitzgeralds", about a retired widower and his three sons

Cast as Indiana University basketball coach Bobby Knight in the ESPN biopic "A Season on the Brink"

Cast in Spike Lee's "She Hate Me"

Starred with Ethan Hawke and Laurence Fishburne in "Assault on Precinct 13"

Earned an Emmy nomination for his role as Father Domenic 'Spags' Spagnolia in Showtime's "Our Fathers," an adaptation of David France's epic book about the sex scandals in the Roman Catholic Church

Starred in "10th and Wolf" an indie film based on a story by Bobby Moresco and Chazz Palminteri

Cast in the Pixar animated feature, "Ratatouille"