In a 2021 Songfacts interview
, Smith explained how the tune came together: "That song started with a riff. The riff you hear at the top of the song really sets the tone for a hopeful moving on from a heartbreak situation. I've always loved guitar riffs that go along with the melody of the verse. And Casey Beathard had the idea for 'This Ain't That Song,' and I loved the way that it flipped from a heartbreak song to a moving on song."