Born in New Haven, Connecticut, USA. Johnson studied music and the piano while he played jazz in high school bands and in the Air Force. When he was discharged he went to Los Angeles where he earned a living writing arrangements while involved in the avant garde jazz scene which centered on musicians such as Ornette Coleman and Paul Bley. In the 60s Johnson went to New York where he played briefly with Charles Mingus, with the Rod Levitt Octet and singer Yolande Bavan and led his own trio. From the 70s Johnson worked increasingly arranging commercial music but did arrangements for a variety of Mingus groups (1971-78) and for the Lee Konitz Nonet among others. In 1984 Johnson was involved in work on the movie The Cotton Club the score of which sought to recreate the sound of Duke Ellington’s classic band of the late 20s and early 30s. Johnson is also an acute jazz journalist and photographer.