An early musical success for McCann was his winning of a Navy talent contest for singing; this led to an appearance on The Ed Sullivan Show. McCann’s main career began in the early 1960s when he recorded as a pianist with his trio for Pacific Jazz Records.
In 1969, Atlantic Records released Swiss Movement, a recording of McCann with frequent collaborator, saxophonist Eddie Harris, and guest trumpeter Benny Bailey at that year’s Montreux Jazz Festival. The album contained the song “Compared To What”, and both the album and the single were huge Billboard pop chart successes. “Compared To What” featured political criticism of the Vietnam War. The song was not written by McCann; fellow Atlantic composer/artist Eugene McDaniels wrote it years earlier. “Compared To What” was initially recorded and released by soul vocalist Roberta Flack. Her version appeared as the opening track on her debut recording, First Take (1969).
After the success of Swiss Movement, McCann — primarily a piano player — began to emphasize his rough-hewn vocals more. He became an innovator in the soul jazz style, merging jazz with funk, soul and world rhythms; much of his early 1970s music prefigures the Stevie Wonder albums of that decade. He was among the first jazz musicians to include electric piano, clavinet, and synthesizer in his music.