Who is the singer behind "Spirit in the Sky"?

One-hit wonders get a bad rap, but some of them are absolute bangers. "Spirit in the Sky" is probably one of the best examples. Over 55 years after its 1969 release, it's still showing up in movies like "This is the End," "Aquaman and the Lost Kingdom," and this year's "Final Destination Bloodlines." It's the kind of song that makes you wonder if maybe having one massive, undeniable hit is better than a dozen forgettable tracks. Who was the artist behind "Spirit in the Sky"?