Kammala wannan jumla: O'Neill ya kasance zakara na NCAA sau uku a kan zobba, ya lashe gasar a 1987, 1988, da 1989, da kuma rike da mafi girma na matsakaicin matsayi (9.93) a 1987 da 1989. Bayan kwaleji, ya ci gaba da gasa a duniya. O'Neill ya zo na huɗu a gasar cin kofin duniya ta wasan motsa jiki ta 1992, mafi girman mazajen Amurka da suka gama, sannan ya zama Ba'amurke na farko da ya lashe lambar yabo a gasar cin kofin duniya a cikin shekaru 15 lokacin da ya lashe lambar azurfa a zoben maza a gasar
1994 Gasar Gasar Gymnastics ta Duniya a Brisbane.