Douglass Dumbrille was born in Hamilton, Ontario. As a young man, he was employed as a bank clerk in Hamilton while pursuing an interest in acting. He eventually left banking to work with a stock company that led him to Chicago, Illinois, and a job with another stock company that toured the United States. In 1913, the East Coast film industry was flourishing and that year he appeared in the film What Eighty Million Women Want, but it would be another 11 years before he appeared on screen again. In 1924, he made his Broadway debut and worked off and on in the theatre for several years while supplementing his income by selling such products as car accessories, tea, insurance, real estate, and books.
During the Great Depression, Dumbrille moved to the West Coast of the U.S., where he specialized in playing secondary character roles alongside the great stars of the day. His physical appearance and suave voice equipped him for roles as slick politician, corrupt businessman, crooked sheriff, or unscrupulous lawyer. A consummate professional, he was highly regarded by the studios and was sought out by Cecil B. DeMille, Frank Capra, Hal Roach and other prominent Hollywood filmmakers. A friend of fellow Canadian-born director Allan Dwan, Dumbrille played Athos in Dwan’s 1939 adaptation of The Three Musketeers.
In a long and successful career, Douglass Dumbrille had roles in more than 200 motion pictures and, with the advent of television, made numerous appearances in the 1950s and 1960s. He had the ability to project a balance of menace and pomposity in roles as the "heavy" in comedy films, such as those of the Marx Brothers or Abbott and Costello. He played similar roles in Capra's 1934 film Broadway Bill and the 1950 remake, Riding High. He also appeared in DeMille's 1938 version of The Buccaneer and twenty years later in the 1958 color remake.
Also working in television, Dumbrille was cast in six episodes of the religion anthology series, Crossroads. He portrayed Senator Bates in "Thanksgiving Prayer" (1956) with Ron Hagerthy of Sky King. Dumbrille then portrayed Mr. Willoughby in "Big Sombrero" (1957). In 1958, he was cast as Mayor John Geary in three episodes of the NBC western series, The Californians. He subsequently guest-starred in Frank Aletter's CBS sitcom, Bringing Up Buddy.
Dumbrille made two guest appearances as a judge on CBS's Perry Mason; in 1964 he played Judge Robert Adler in "The Case of the Latent Lover", and in 1965 he played an unnamed judge in "The Case of the Duplicate Case". In his final television role, he portrayed a doctor in episode 10 of Batman in February, 1966.
After a long marriage, Dumbrille's wife, Jessie Lawson, mother of their son John and daughter Douglass (Dougie), died in 1958. In 1960, at the age of seventy, Dumbrille caused a stir when he married Patricia Mowbray, the 28-year-old daughter of his friend and fellow actor, Alan Mowbray. In response to criticism of the May–December marriage, Dumbrille provided a succinct answer: "Age doesn’t mean a blasted thing. The important thing is whether two people can be happy together. Pat and I agreed that I had some years left and we could best share them together. We don’t give a continental damn what other people think."
Douglass Dumbrille died of a heart attack on April 2, 1974 in Woodland Hills, California.