While serving in the military during World War II, Cavanaugh met guitarist Al Viola and bassist Lloyd Pratt, with whom he formed a trio. After the war's end they performed together in the style of the Nat King Cole Trio, scoring a number of hits in the late 1940s including "The Three Bears", "Walkin' My Baby Back Home", and "All of Me". The trio appeared in the films A Song Is Born, Big City, Lullaby of Broadway (with Doris Day) and Romance on the High Seas (Doris Day's first film, in 1948).
Additionally, they played on Frank Sinatra's Songs by Sinatra radio program and on The Jack Paar Show. He played in Los Angeles area nightclubs through the 1990s, both in a trio setting (with Viola for many years) and as a septet, the Page 7. He also recorded with Bobby Woods & Les Deux Love Orchestra. Cavanaugh recorded for MGM, Capitol, RCA, Star Line, Tiara and Dobre Records over the course of his career, releasing his final Page Cavanaugh Trio CD, Return to Elegance, in 2006. The Page Cavanaugh Trio may also be seen and heard in the 1958 horror movie, "Frankenstein's Daughter", directed by Richard E Cunha and produced for $60,000 by Layton Film Productions.
His Page Cavanaugh Trio played in various formations, one of the with Las Vegas bassist Milan Rezabek in Sahara Casino in Lake Tahoe, NV (1968-1970).