He was born in Houston, Texas, and moved to Los Angeles, California, at the age of nine. By this time he had begun to study piano and trombone. He played with Frank Morgan, Don Cherry, and Billy Higgins as a teenager. After service in the Air Force in Wyoming, he returned to Los Angeles and played trombone with various bands, notably Lionel Hampton (1959–61). Soon after, though, he quit playing trombone and focused on piano.
In 1961 Tapscott formed the Pan Afrikan Peoples Arkestra, with the aim of preserving, developing and performing African-American music. As his vision grew, this became just one part of a larger organization in 1963, the Underground Musicians Association (UGMA), which later changed name to the Union of God's Musicians and Artists Ascension (UGMAA). Arthur Blythe, Stanley Crouch, Butch Morris, Wilber Morris, David Murray, Jimmy Woods, and Guido Sinclair all performed in Tapscott's Arkestra at one time or another. Tapscott and his work are the subjects of the UCLA Horace Tapscott Jazz Collection.
Enthusiasts of his music formed two labels in the 1970s and 1980s, Interplay and Nimbus, for which he recorded.
John Carter, Bobby Bradford, Horace Tapscott-(1969)- West Coast Hot
Horace Tapscott & Pan Afrikan Peoples Arkestra-(1978)- Flight 17
Horace Tapscott-(1969)- The Giant Is Awakened
Horace Tapscott-(1978)- Song Of The Unsung
Horace Tapscott-(1979)- In New York
Horace Tapscott-(1979)- Lighthouse 79 Vol. 1
Horace Tapscott-(1979)- Lighthouse 79 Vol. 2
Horace Tapscott-(1980)- Autumn Colours
Horace Tapscott-(1981)- Live At Lobero Volume 1
Horace Tapscott-(1983)- Faith
Horace Tapscott-(1991)- The Dark Tree
Horace Tapscott-(1995)- Aiee! the Phantom
Horace Tapscott-(1997)- Thoughts of Dar Es Salaam
Horace Tapscott-(1998)- Dissent or Descent
