Gillespie, Dizzy (John Birks Gillespie), 1917-93, American jazz musician and composer, b. Cheraw, S.C. He began to play the trumpet at 15 and later studied harmony and theory at Laurinburg Institute, N.C. He played with the bands of Cab Calloway and Billy Eckstine. Gillespie and Charlie "Bird" Parker are considered the leaders of the bop (or bebop) movement in modern jazz. Gillespie's playing was characterized by intelligent musicianship and technical facility.