"Story of My Life" is a mid-tempo, guitar-driven folk-pop song with influences of arena rock, alternative rock and neo folk. It runs for a total of four minutes and five seconds. Idolator compared the song to the works of Ed Sheeran, Coldplay and Mumford & Sons.
Sam Lanksy of Idolator called the song "surprisingly great" and noted it was a "mature midpoint" between the group's signature "rollicking pop-rock confection[s]" and "dreary ballads". Lanksy additionally called the song "merciful" and complimented it for using alternative-folk influences without "smell[ing] like spilled beer". Amy Sciarretto of PopCrush gave the song 4 out of 5 stars, calling it a "contemplative, acoustic guitar-driven song" and complimenting it for being "more memorable" than any of the group's previous works. Sciarretto noted that the song would resonate with listeners of many different ages and showed that One Direction "isn't just a boy band"; although noted the song was not as "crazy catchy" as their previous songs. Lauren Wheeler of TheCelebrityCafe.com gave the song 5 out of 5 stars noting that the lyrics were "reflective" and "much deeper than some of their bigger hits." Wheeler added that the song showed that One Direction "not only have range, but also have matured through their music."