Waldron went on to work with Ike Quebec in New York in 1950 and made his recording debut with the saxophonist in 1952. They played at Café Society Downtown on Mondays for six or seven months, which helped Waldron gain exposure and more work. Waldron worked frequently with Charles Mingus from 1954 to 1956, as part of the latter's jazz composers' workshop. He was pianist on several Mingus recordings, including "Pithecanthropus Erectus", which was a key development in the movement towards freer collective improvisation in jazz. In 1955, Waldron worked with Lucky Millinder and Lucky Thompson. Waldron formed his own band in 1956, which consisted of Idrees Sulieman (trumpet), Gigi Gryce (alto saxophone), Julian Euell (bass), and Arthur Edgehill (drums). This band recorded Waldron's first release as a leader, "Mal-1", in November of that year. Waldron was Billie Holiday's regular accompanist from April 1957 until her death in July 1959, including for the all-star television broadcast "The Sound of Jazz".