His brother David taught John how to play guitar when John was 14. For five years He was a mailman and also served in the Army before beginning his musical career in Chicago. In the late 1960s, he delivered mail during the day, and in the evening, sang at open-mic evenings at the Fifth Peg on Armitage Avenue. Prine was initially a spectator, reluctant to perform, but eventually did so in response to a "You think you can do better?" comment made to him by another performer.