His first steady gigs of note were with Shirley Horn and Buck Hill. In the 1960’s he toured with Jimmy Smith, Wes Montgomery, Eddie Harris, and Pharoah Sanders. In 1970 he joined Herbie Hancock’s Sextet, and after that band broke up in 1973 he joined first McCoy Tyner (two years) and then Stan Getz (four). In the 1980’s Hart was a regular with many bands and leaders: Gerry Mulligan, Billy Harper, Clark Terry, The New York Jazz Quartet, the Jazztet, Mingus Dynasty and most extensively with Quest (with David Liebman, Ritchie Beirach, and Ron McClure). In the 1990’s Hart was a member of the Charles Lloyd, Joe Lovano, and Tom Harrell groups, and in 1999 he began performing with the Three Tenors (Liebman, Lovano, and Michael Brecker). He is on about 500 hundred records as a sideman.