Eilish credits "Bury a Friend" as the main inspiration for its parent album, stating that "the entire album clicked" in her head when the song was created, and added that she "immediately knew what it was going to be about, what the visuals were going to be, and everything in terms of how [she] wanted it to be perceived. It inspired what the album is about."
British rapper Crooks makes an uncredited appearance on the track. Eilish discovered the artist on social media; Crooks repeatedly tagged pictures of himself with the caption "Where's Billie at?" on her Instagram comments, prompting her to think "Who the fuck is this kid?" She decided to make his acquaintance and found him "super funny and [...] kind of cute" and the two soon became best friends.