Zeitlin has one of the more unusual "day gigs" for a jazz musician: he's a psychiatrist. Zeitlin's parents were involved in both music and medicine. They started him on the piano at age two; he continued to study classical music while in elementary school, then began playing jazz in high school. Zeitlin began playing professionally in and around his hometown of Chicago as a teenager. In college, he studied composition and theory with George Russell, Alexander Tcherepnin, and Robert Muczynski while simultaneously pursuing studies in medicine. While a student at Columbia University in New York City, Zeitlin auditioned for the legendary producer/talent scout John Hammond; Hammond was sufficiently impressed to produce several records by Zeitlin in the '60s.