Raised in Swampscott, Massachusetts
After college, briefly worked as a newspaper reporter in Boston
Held various jobs from ditch digger to bank clerk
Enlisted in Army during WWI; promoted to colonel; served in France with the 26th Division; fell victim to poison gas attack which permanently affected his vocal chords; mustered out in 1919
After military service, moved to California
Worked as a real estate agent; bought pineapple plantations in Guatemela and California; made first fortune
First film appearances as extra and stuntman at Universal (date approximate)
Landed first film role in "Tearin' Into Trouble"
Accident while working as a stuntman knocked out front teeth and had decisive impact on career giving him a great asset, false teeth which he removed or restored from part to part
Meaty supporting role in "The Wedding Night" assured him a full-time movie career; originally had been cast in smaller role but producer Samuel Goldwyn was impressed enough to cast him in bigger part; also marked first screen collaboration with actor Gary Cooper
Signed to contract with Goldwyn
Received first Oscar Oscar for Best Supporting Actor (initial presentation of award in this category) for Wyler and Hawks' "Come and Get It"
Earned second supporting actor Oscar for David Butler's "Kentucky"
Won third supporting actor Oscar for William Wyler's "The Westerner"; played Judge Roy Bean; first performer to win more than two awards and (to date) only male performer to achieve this distinction
Nominated for Best Supporting Actor in "Sergeant York"; only time nominated that he failed to win; most notable screen collaboration with Gary Cooper
Played Eddie, the rummy, in Howard Hawks' "To Have and Have Not"
Appeared in John Ford's classic "My Darling Clementine"
Had another turn for Hawks in "Red River"
Final screen appearance in support of Cooper in "Task Force"
Tormented Kirk Douglas with a song in Raoul Walsh's "Along the Great Divide"
Portrayed Ben Tatem in Anthony Mann's "The Far Country"
Played Doc in John Sturges' "Bad Day at Black Rock"
Starred as Grandpa Amos McCoy on popular TV series "The Real McCoys" (ABC, 1957-1962; CBS, 1962-1963); reportedly Brennan owned fifty percent of the series
Delivered tour de force performance as Stumpy in Hawks' "Rio Bravo", a culmination of the loyal, crabby old men he had played for over twenty years
Portrayed chairman of the board Walter Andrews, a cantankerous millionaire, in ABC's sitcom "The Tycoon"
Starred in title role of ABC's "The Guns of Will Sonnett"; co-star Dack Rambo played grandson Jeff