Recalling the song's creation in his authorised biography, Many Years from Now (1997), McCartney says he wrote "Every Little Thing" in the music room at the London home of his then-girlfriend Jane Asher, where he was living at the time.

[1][2] Other sources, citing a 1964 interview with McCartney, place the song's origins at Atlantic City in the United States, where the Beatles stopped over in late August that same year during their US tour.

[13] In their respective line-ups for the song, authors Ian MacDonald and Kenneth Womack each credit Harrison for the lead guitar part, played on a Rickenbacker 12-string, and Lennon as the acoustic rhythm guitarist.

[18] While considering the Lennon–McCartney compositions on Beatles for Sale to be relatively uninspired, author Mark Hertsgaard pairs "Every Little Thing" with "I Don't Want to Spoil the Party" as tracks that demonstrate "how the band, thanks largely to John and Paul's extraordinary singing, could make unremarkable material sound richer than it really was".

While noting the Beatles' fatigue on the album in reaction to their punishing schedule in 1964, Ewing views McCartney's narrative as "distinctly melancholy, his 'yes, I know I'm a lucky guy' sounding like an attempt to convince himself of that".

[21] This song was revisited briefly during the stressful rehearsals that were recorded for the Beatles' Get Back/Let It Be project – Harrison describes it as "a good one" before starting to play the lick, McCartney joining in on vocals.