The song is about a toxic relationship Avril maintained while suffering from Lyme disease.
It was released as the fourth single from the album on June 28, 2019.
SPIN's Zoe Camp was unfavorable in her review, stating that Lavigne took a "technically slack (read: bored-sounding) stab at soul on 'I Fell in Love with the Devil'" and offered a "not-hot take on an abusive relationship".
Alexandra Pollard of The Independent was positive in her review of the song, claiming "Lavigne's voice reaches new heights too-particularly on 'I Fell in Love with the Devil', an ominous, tightly crafted rumination on toxic relationships".
Rolling Stone's Emily Zemler labeled it an "emotive anthem" and a "heartbreak-tinged number", and went on to claim that "'I Fell in Love with the Devil' is a much more emotionally-driven track than her previous singles, 'Head Above Water' and 'Dumb Blonde'".