McGrath made a sensational professional debut, winning the first PBA tournament he entered in 1965 at Portland, Ore. at age 19. He also was the hero in the first USBC Open Championships Classic division team rolloff series in 1970 at Knoxville, Tenn. when he converted the difficult 1-3-6-9 spare that brought his Merchant Enterprises the title by eight pins. He later added two other USBC titles. In 1970, he became the first bowler to win consecutive PBA National Tournament titles. He retired from the tour with 10 titles.