From Bulbapedia, the community-driven Pokémon encyclopedia.
John Loeffler (sometimes credited as John Leffler or Joe Loeffler) is a former producer, writer, and singer for the English dub of the Pokémon anime.
As CEO of Rave Music, he was in charge of all the music for the U.S. localization of the show from its inception to the seventeenth season. Up until this time, Loeffler produced all of the original music for the series, including album releases, movie scores, dub scores, and the Pokémon Live! show. He has written, composed, or arranged a majority of the tracks with many composers including John Siegler (also of Rave), David Wolfert, and Norman J. Grossfeld, producer of the 4Kids dub. He was involved in producing the opening themes from seasons 1-4, and has written and produced the English opening themes from the ninth season to the sixteenth season of the anime. John is also respectably credited for composing and writing the lyrics of the seventeenth season opening theme as the song was based on the first season's opening theme.
After producing Pokémon Theme (Version XY), he and David Wolfert were replaced by Ed Goldfarb.
He has provided lead vocals for:
Profile and Interview with John Loeffler, 2000