The song reached the top 40 charts in the United Kingdom, Canada, Austria, and the Netherlands.

Written by lead vocalist Roland Gift and bassist David Steele, "I'm Not the Man I Used to Be" contains prominent drum beats with keyboards and finger-picked guitar accompaniment.

The song utilises, throughout the track, a sample from "Funky Drummer" by James Brown.

[1] Allmusic writer Jo-Ann Greene described the song as having "a futuristic jungle beat and an almost housey production".

[6] Dave Thompson of Allmusic praised Gift for "[h]is introspective lyrics and almost wistful performance".