Rubuta ci gaba don wannan sakin layi - O'Neill ya kasance zakara na NCAA sau uku a kan zobba, ya lashe a 1987, 1988, da 1989, da kuma rike da mafi girman matsakaicin matsakaici (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 maza na Amurka, sannan ya zama Ba'amurke na farko da ya lashe lambar yabo a gasar zakarun duniya a cikin shekaru 15 lokacin da ya lashe lambar azurfa a zoben maza a gasar cin kofin duniya ta wasan motsa jiki ta 1994
a birnin Brisbane.