Dumbrille was born in Hamilton, Ontario. As a young man, he worked as a bank clerk in his home town of Hamilton while at the same time pursuing an interest in acting. He eventually left banking to work with a stock company that led him to Chicago, Illinois and to a job there with another stock company that toured across the United States. In 1913, the east coast film industry was still 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 continued working off and on in the theatre for several years while supplementing his income with a variety sales jobs.

In the Great Depression of the 1930s, when jobs were scarce, Hollywood films provided a brief escape from the stresses of the difficult times and the film industry still offered an opportunity for quality actors to earn a decent living. As such, Dumbrille went to the west coast where he specialized in playing secondary character roles to the great stars of the day. His physical appearance made him perfect for the role of the slick politician, the shyster businessman, the crooked sheriff, or the 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 Hollywood directing greats. A friend of fellow Canadian-born director Allan Dwan, Dumbrille played Athos in Dwan’s 1939 adaptation of The Three Musketeers.

Considered as one of film's great character actors, over his long and successful career Douglass Dumbrille had roles in more than 200 motion pictures and with the advent of television he made numerous appearances in shows throughout the 1950s and 1960s. The respect he earned was such that he played the same role in Capra's 1934 film Broadway Bill and its 1950 remake, and also appeared in DeMille's 1938 version of The Buccaneer and twenty years later in its remake.

After a long marriage, his wife Jessie Lawson died in 1957 and in 1960, at age 70 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 had 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 from a heart attack in 1974 in Woodland Hills, California, and was interred in the Valhalla Memorial Park Cemetery, North Hollywood, California.

A few of his films: