"A Hard Day's Night" is a song by British rock band The Beatles. Written by John Lennon and credited toLennon/McCartney, it was released on the movie soundtrack of the same name in 1964. It was later released as a single, with "I Should Have Known Better" as its B-side.
The song featured prominently on the soundtrack to The Beatles' first feature film, A Hard Day's Night, and was on their album of the same name. The song topped the charts in both the United Kingdom and United States when it was released as a single. Featuring a prominent and unique opening chord, the song's success demonstrated that The Beatles were not a one-hit wonder.
The American and British singles of "A Hard Day's Night" as well as both the American and British albums of the same title all held the top position in their respective charts for a couple of weeks in August 1964, the first time any artist had done this.