Hales studied trumpet briefly in Regina before moving to Chilliwack, BC, in 1947, and 1955-7 attended Westlake College of Modern Music in Los Angeles where his teachers were Ollie Mitchell and Dick Groves. Based thereafter in Vancouver, he initially played and arranged music for Dave Robbins' big band and subsequently led bands in various supper clubs and played in the city's studios. He was music director in 1963 for the Vancouver edition of CBC TV's 'Music Hop' and 1976-7 for CTV's 'Rolf Harris Show,' and composed theme and incidental music for the CBC series 'The Manipulators' and 'The Beachcombers' and for the CBC TV movie 'The Overlanders'. In 1988 he completed a suite, The Beginning of the End, for the closing ceremonies of the Calgary Winter Olympics.

The Bobby Hales Big Band, formed in 1965, was heard often on the CBC's 'Jazz Canadiana' and 'Jazz Radio-Canada,' performed nightly during the Pacific National Exhibition for several years, and in 1977 gave concerts and workshops elsewhere in British Columbia and Alberta. Vancouver's leading jazz orchestra during the 1970s, it made the LP One of My Bags (1975, Centreline 0975) comprising six Hales compositions (eg, Funklicity and Formula #1) and featuring such soloists as the trumpeters Stew Barnett, Don Clark, and Hales himself, the saxophonists Fraser MacPherson, Dave Quarin, Wally Snider, and Jack Stafford, the guitarist Oliver Gannon, the pianist Bob Doyle, and the drummer George Ursan. It continued largely as a commercial orchestra in the 1980s, recording an album of dance-band music, Bobby Hales Big Band, for Centreline late in the decade, accompanying pop performers, and playing for musicals, dances, and conventions.