In August 1964, the Beatles’ “A Hard Day’s Night” reached number one in the United States, becoming the group’s fifth chart-topper in seven months. The achievement underlined the scale of Beatlemania and helped establish a record-breaking year for the band, while the song also served as the title track for their film and soundtrack album.

The Beatles ultimately had seven US number-one singles in 1964, an all-time record, and Lennon–McCartney wrote six of the year’s chart leaders. For a period in August, the song’s US and UK singles and the corresponding albums simultaneously topped their respective charts, another first; its title came from Ringo Starr’s accidental phrase after a long working day and night, while George Harrison created its famous opening chord.