Halfnelson was initially released on Bearsville Records in 1971. Shortly after the release of the album the group changed their name to 'Sparks'. The album was then re-released by Bearsville Records in 1972 as Sparks. The new version of the album featured new artwork that was simpler, displaying the group in more of a classic profile superimposed against a red brick pattern. The single to this reissue "Wonder Girl," became a minor regional hit in Alabama and appeared on the lower end of the Cashbox chart at #92.
Halfnelson has been re-released numerous times since 1972. It is often packaged with the follow-up album A Woofer in Tweeter's Clothing. One such re-issue was released in 1975 to capitalize on the group's success in the UK. This version was titled 2 Originals of Sparks and was packaged as a double-LP in a gatefold sleeve with a 14-page booklet.
The most recent re-issue was produced by Rhino Encore and released in 2008.