It was written by Cassie Davis, Sean Mullins, Ali Tamposi, Olivia Waithe, Talay Riley, and produced by More Mega for Candy's unreleased album Daddy Issues.

Moving away from the past rap sound from her 2014 EP Opulence, the track is an electropop song that revolves around the pursuit of happiness and the struggles involved.

[2] Produced by More Mega, "Happy Days" is written by Cassie Davis, Sean Mullins, Ali Tamposi, Olivia Waithe, Talay Riley.

[5][6] In 2017, the release for Daddy Issues was canceled after Candy left RCA to record an extended play (EP) that returned to her original punk-inspired rap sound.

[10] Mike Wass from Idolator gave a positive review, noting its accessibility compared to Candy's past material as well as its relatable chorus.

[3] Wass was more critical of it during his review of the follow-up single "Living Out Loud" (2017), including it in his list of the "string of flops" released to promote Daddy Issues.

[12] BlackBook's Justin Moran stated that the song marked Candy's "official transition from underground rap to provocative pop.