From Bulbapedia, the community-driven Pokémon encyclopedia.
David Kos "Music Man" Rolfe, born November 23, 1968 in Brooklyn, New York, USA, is an artist who has written and performed songs for the English dub of the Pokémon anime. He has a record label from Warner/Chappell Production Music and continues to make music as of 2017.
Working under the 4Kids dub, he performed five English theme songs, namely Born to Be a Winner, Believe in Me, I Wanna Be a Hero, This Dream, and Unbeatable. He currently lives in New York City.