A 45-minute demo that reached number one
In 1973, at TK Studios in Hialeah, Florida, Harry Wayne Casey and Richard Finch recorded a backing track in about 45 minutes. Casey played keyboards. Finch played bass and drums. Jerome Smith, their partner in the group that became KC and the Sunshine Band, played electric guitar. The piece was a demo. It is also one of the first pop hits to use a drum machine. They had not written it for George McCrae.
McCrae was in the studio that day and sang it in a high, light voice. TK Records released Rock Your Baby in May 1974. The B-side was a second part of the same track. The 7-inch runs 3 minutes and 14 seconds. On the album of the same name, the song stretches to 6 minutes and 24 seconds. Casey and Finch produced both. McCrae was already singing around Miami, and he was married to the singer Gwen McCrae, but this was his first single, and the one that travelled.
In July 1974 the single spent two weeks at number one on the Billboard Hot 100 and also topped the R&B chart. In Britain, on the Jay Boy label, it was number one for three weeks that same month. Sales later passed 11 million copies, a figure reached by only a small set of physical singles. What you hear is plain: a steady dance beat, a short guitar figure, and McCrae’s voice kept up above both. The critic Robert Christgau described it as Memphis soul crossed with disco, held together by a hook.
I’d give my eyetooth to have written that.
(John Lennon, 1975 interview)

Lennon was talking about his own 1974 single, Whatever Gets You thru the Night, and he said Rock Your Baby had pushed him toward it. Benny Andersson and Björn Ulvaeus have also named the McCrae record among the songs in the room when ABBA wrote Dancing Queen. In 2022, Rolling Stone placed Rock Your Baby at number 158 on a list of the 200 greatest dance songs. McCrae never had another hit of this size. The follow-up single, I Can’t Leave You Alone, came out later in 1974 and did not repeat the run. The same TK team, under the name KC and the Sunshine Band, broke through the next year with Get Down Tonight and That’s the Way (I Like It). Rock Your Baby is the record that showed the Hialeah method could top the pop chart before the band’s own name did. The work itself was still that demo, cut in under an hour and sung by the man who happened to be standing there.