Pretty much The Wrecking Crew played on all their songs.
The Wrecking Crew must have laughed themselves silly when this hit #1 😃
Danny Bonaduce likes to tell the story (possibly apocryphal) about how the readers of one or another of the teen music magazines voted him No. 1 (or No. 2) bass player in the world, neck and neck with Paul McCartney. So, it may have been Carol Kaye or Ray Pohlman or Lyle Ritz on the record, but Danny was getting the fan mail.
This was part of the "sunshine pop" genre of the late 1960s/early 1970s.
Really, the Partridge Family put out some fantastic pop music. Even though it was performed by professionals (Wrecking Crew) and not actually performed by the TV actors. Though David Cassidy and Shirley Jones did actually sing. The rest of them sort of just shuffled around and tapped on a tambourine or something.