Thomas worked with his brother Jack's Crescent Orchestra in 1913 -- a high-profile arrangement, as the jazz standard "Tiger Rag" was colloquially known as "Play Jack Carey." He paraded with the Tuxedo, Superior, and Eagle bands, acquired the nickname Papa Mutt, and on Joe Oliver's recommendation replaced Lewis Matthews with Kid Ory's band in 1914. Mutt hit the road in 1917 in the company of pianist Steve Lewis, clarinetist Johnny Dodds, and drummer Max Hill as the musical component of Mack & Mack's Merrymakers of Mirth, a vaudeville revue that worked the TOBA circuit. After the show hit Chicago, Dodds returned to New Orleans to work with Ory while Carey stayed on, gigging at the Pekin Cafe and with Lawrence Duhe at the Dreamland.

Within months Carey was back in New Orleans, serving as second trumpet for Chris Kelly at the Bull's Club and performing at a roadhouse in Bucktown with a band led by Wade Whaley, a clarinetist with whom he made ends meet by cleaning and pressing suits. When in 1919 King Oliver asked Ory to join him in Chicago, the trombonist chose a roundabout route, migrating all the way to the West Coast where he was soon gigging at the Cadillac Café in Watts with a group of players imported from New Orleans, including Whaley and Papa Mutt. Ory's band made a splash in Los Angeles and San Francisco, and had a chance to make records in June 1922, backing vaudevillian blues singers Roberta Dudley and Ruth Lee and waxing a pair of instrumentals, the famous "Ory's Creole Trombone" and a raggy stomp bearing the title "Society Blues" -- these were the first recordings ever to be made by Afro-American musicians from New Orleans.

After Ory went east to finally hook up with Oliver in 1925, the band became known as Mutt Carey & His Jeffersonians. This group secured regular work by providing atmospheric background music during the production of silent movies. Ory rejoined the band in 1930 but gigs dried up as the Great Depression forced them off the scene. Years passed, during which Carey worked as a postman and a Pullman porter. During the spring of 1944 Papa Mutt was heard on a radio program hosted by jazz fan Orson Welles with a group that included Ory, clarinetist Jimmie Noone, bassist Ed Garland, and drummer Zutty Singleton. Carey and Ory made records together in 1944 and 1945. They held down an extended engagement at the Green Room in San Francisco and appeared with Louis Armstrong in New Orleans, a motion picture released in 1947.

On August 30, 1946, Papa Mutt recorded six duets with singing pianist Hociel Thomas in San Francisco. The following year he visited the East Coast and formed his own band, with clarinetist Albert Nicholas in the front line. This group, which he called his New Yorkers, made a handful of influential recordings in November 1947. Carey returned to California and put together his last group, but only gigged with them briefly. A few months later, he was in the process of assembling another unit when he suffered a fatal heart attack in Elsinore, CA, on September 3, 1948. Mutt Carey's legacy may be savored on compact disc reissues of his work as a leader, the studio and air shot recordings with Ory, and those delicious duets he did up with Hociel Thomas near the end of the summer of 1946.