The song was produced by Alan Osmond. It broke from the group's string of harder rock-sounding hits through the early 1970s and began a string in which the band began playing up their image as teen idols and began releasing love ballads as singles. As with other songs on The Plan, "Let Me In" carries a dual message of secular and Mormon/Christian themes, both as a straightforward love song and as a plea to God for redemption from the singer's past abandonment of Him and a request to return to His love (akin to the parable of the prodigal son). The song marked the return of the formula of Merrill and Donny Osmond alternating on lead vocals, the formula the band had used while Donny was a boy soprano; by this point, Donny's voice had lowered to the tenor/baritone range he would have in adulthood. Merrill sang on the verses, with Donny (aided by Alan and Wayne in unison) singing the chorus.