There was a big legal kerfuffle over this song, as Motown Records claimed they owned it. The Isleys formed their own label, T-neck Records (named for their town: Teaneck, New Jersey), in 1964, but signed with Atlantic later that year. In 1965, Atlantic dropped them and Motown picked them up, putting them on their Tamla imprint and having them record songs written by the Holland-Dozier-Holland team. They had a minor hit for the label with "This Old Heart Of Mine
," but in December 1968 they left Motown to once again record on T-neck.
When this song took off, Motwon head Berry Gordy filed a lawsuit claiming The Isley's were still under contract when they recorded it. The court case went on for 18 years before a federal judge ruled that The Isley Brothers had recorded it after the Motown contract had lapsed.