"
Happy Jack" is a song by the British rock band
The Who. It was released as a single in December 1966 in the UK, peaking at No. 3 in the charts. It peaked at No. 1 in Canada. It was also their first top forty hit in the United States, where it was released in March 1967 and peaked at No. 24. It was included on the American version of their second album,
Happy Jack, originally titled
A Quick One in the UK.