[2] Composed primarily of pop standards such as "Ol' Man River" and "For Once in My Life" (later a major hit for Motown labelmate Stevie Wonder), and similar songs written by Holland-Dozier-Holland and other Motown staff songwriters, the Mellow Mood album was part of Motown chief Berry Gordy's crossover plans for the group.

Gordy wanted the Temptations, already the most popular male group among black audiences, to attract a large white fanbase and be able to secure playdates at supper clubs like the Copacabana, where the group had first performed in the summer of 1967.

The Temptations themselves, and Paul Williams in particular, were worried about appearing as sell-outs to their black fans and the radio DJs who had made them popular in the first place.

However, both pop and soul fans responded to the Mellow Mood album, and the Temptations reached Gordy's desired goal of crossing over to white audiences.

"Ol' Man River" was already present in the Temptations' performance repertoire as bass Melvin Franklin's solo spot, and "For Once in My Life" soon became a solo showcase for Williams, who performed a particularly acclaimed version of the song for the TCB television special in late 1968.