Once Lewis moved to New York, Clarke introduced him to Dizzy Gillespie's bop-style big band. He successfully auditioned by playing a song called "Bright Lights" that he had written for the band he and Clarke played for in the army. The tune he originally played for Gillespie, renamed "Two Bass Hit", became an instant success. Lewis composed, arranged and played piano for the band from 1946 until 1948 after the band made a concert tour of Europe. When Lewis returned from the tour with Gillespie's band, he left it to work individually. Lewis was an accompanist for Charlie Parker and played on some of Parker's famous recordings, such as "Parker's Mood" (1948) and "Blues for Alice" (1951), but also collaborated with other prominent jazz artists such as Lester Young, Ella Fitzgerald and Illinois Jacquet.