As well as his international titles, Foster was twice NCAA outdoor champion (1978 and 1980) in the 110 meter hurdles and was the NCAA 200 meter dash champion in 1979. He won 10 U.S. national titles, four of them outdoors in the 110 meter hurdles (1981, 1983, 1986, and 1987) and six indoors, in the 60 yard hurdles (1983, 1984, 1985), 55 meter hurdles (1987, 1988) and 60 meter hurdles (1991).
He broke the indoor world record for the 50 meter hurdles in 1985 (6.35 seconds) and tied that mark in 1987. He also broke the 60 meter hurdle indoor world record in 1987 with a time of 7.36. He was the American Record Holder in the 110 meter hurdles at 13.22 seconds while competing for UCLA, second at the time only to Cuba's world record holder Alejandro Casañas. His personal best time for the 110 meter hurdles was 13.03, run at the Weltklasse Zürich meet in 1981 in which Renaldo Nehemiah became the first man the break the 13 second barrier, with his 12.93. This once again made Foster the second-fastest hurdler of all time. Foster was ranked in the top ten hurdlers in the world for 15 out of 16 years 1977 to 1992. Five of those years, he was ranked number one, 1982, 1983, 1986, 1987 and 1991.