There were several double bass players in his family, but he did not meet them. He studied with several teachers. He went to the Juilliard School. In 1962 he became famous when he was a soloist in a nationally televised New York Philharmonic Young People's Concert, conducted by Leonard Bernstein. On that famous telecast, Karr performed "The Swan" from "Carnival of the Animals" by Camille Saint-Saëns.