He died in a Manhattan hospital, apparently of a heart attack, shortly after undergoing spinal surgery, said Devra Hall Levy, a family spokeswoman.
Mr. Powell spent most of his career as a sideman, but he made the most of his moments in the spotlight. His brief but lively solo on Basie's 1955 recording of April in Paris" helped make it one of the most popular numbers in the band's repertory.
Mr. Powell was admired by critics and fellow musicians. Writing in The New York Times in 1984, John S. Wilson praised him for his innate elegance" and his mellow, full-bodied sound."
Mr. Powell was with Basie from 1951 to 1963 and later returned to the band on special occasions and performed with Basie alumni ensembles. In a 1997 interview with the Online Trombone Journal (trombone.org), he said he remained so closely identified with Basie that people still ask me, 'Is the band in town?'