William Harrison Dempsey was born in Manassa, Colorado Dempsey Jack Dempsey, Boxing Champion, Dies at 87 Jack Dempsey, 87, is Dead; Boxing Champion of 1920's Jack Dempsey, Boxing Champion, Dies at 87 Dempsey Dempsey He later became a restaurant owner legendary heavyweight champion. legendary heavyweight champion. legendary heavyweight champion. Jack Dempsey, Boxing Champion, Dies at 87 Jack Dempsey, Boxing Champion, Dies at 87 Dempsey legendary heavyweight champion. legendary heavyweight champion.