Carey was born in Hahnville, Louisiana, and moved to New Orleans with his family in his youth. His older brother Jack Carey was a trombone player and bandleader; Mutt was playing cornet in his brother's band by about 1912. He worked with Kid Ory on and off through the 1910s, and went to California with Ory in late 1919, making his first recordings there about 1921. When Ory moved to Chicago Carey took over leadership of the band which was based in Los Angeles, California through the 1930s. In 1944 he rejoined Ory, and helped revive interest in traditional jazz on the West Coast. He left Ory's band in 1947 to lead a group under his own name. He died in Elsinore (near San Francisco, California) on September 3, 1948.