The first vocalist to sing "I love rock n roll" was Alan Merrill of The Arrows in 1975 released on RAK records UK, he co-wrote the song as well. Joan Jett and the Blackhearts recorded a very successful cover version in 1982.
I think it was Tom Jones, but unfortunately, the Wikipedia page doesn't give a straight answer. It talks a lot about the original version, but apparently couldn't be bothered to explicitly mention who sang it. It lists the songs' writers as George Jackson and Tom Jones. I have included a link below.
The most popular version is the Bob Seger version.
Alan Merrill was the original vocalist with The Arrows in 1975, and it was produced by Mickie Most on RAK records written by Alan Merrill and Jake Hooker of the band Arrows . Later covered with great success by both Joan Jett and Britney Spears.
Aalon
Rick Derringer
Is it possibly Ghost by Slash? "Kill the ghost That hides in your soul Rock 'n' Roll Rock 'n' Roll"
The Rolling Stones The Rolling Stones
Kiss.
Nazareth - Somebody To Roll
Aalon
I Love Rock 'n' Roll was created in 1975.
Rick Derringer
Is it possibly Ghost by Slash? "Kill the ghost That hides in your soul Rock 'n' Roll Rock 'n' Roll"
Rock n' Roll Love Letter was created in 1976-03.
The Rolling Stones The Rolling Stones
Kiss.
Acdc
Ray Davies or Paul Rogers Bad Company
Tré Cool
Bob Seger