Many of the episode titles are also the names of songs; "He Ain't Heavy, He's My Brother" was written by Bobby Scott and Bob Russell and recorded separately by Kelly Gordon, The Hollies, and Neil Diamond in different years.
In 1975, Olivia Newton-John covered the song on her album Clearly Love and included it as the B-side on her single from the same album, "Let It Shine", which went to No. 1 on the US Adult Contemporary chart.