Jimmy Mack is based on an actual person -
The song, with lead vocal by Vandellas' lead singer Matha Reeves, is narrated by a woman who longs for her boyfriend, named "Jimmy Mack", to return to her. The narrator is being courted by another suitor, whom she notes "talks just as sweet as" her long-gone Jimmy, and hopes for him to return before her resistance is worn down.
The inspiration for this song came from a 1964 music industry awards dinner, which Lamont Dozer attended. At the ceremony the mother of the songwriter Ronnie Mack accepted an award for her son, who had recently died, for his composition He's So Fine. Under pressure to come up with a hit for Reeves and the Vandellas, Dozier and the team penned this song in part a tribute to Mack the writer.
"Jimmy Mack" was originally recorded in 1964 when Annette Beard was still apart of the group. The song was shelved because the Motown Quality Control team felt the recording was not suitable for release with the Vietnam War going on. Like Smokey Robinson & the Miracles' later hit, "The Tears of a Clown", "Jimmy Mack" was pulled from the vault two years later and released as a single in early 1967. By that time, the Vietnam War had become a highly debated issue among the American public. Thus, Reeves' sentiment that her "Jimmy Mack" return took on a different meaning for many listeners, particularly those stationed overseas.
- copied from Wikipedia