 Okonkwo was a member of Enyimba's winning side in the 2003 MTN CAF Champions League and 2004 MTN CAF Champions League finals.During his two-year stay in South Africa he was arguably one of the club's most influential players even scoring the decisive goal against his former club Enyimba to lead the Johannesburg-based club Orlando Pirates to the 2006 MTN CAF Champions League semifinals..

Okonkwo caused a stir in Europe by signing a pre-contract agreement with German side FC Köln only to leave the club a week later to sign a four-year deal at Swiss side FC Zürich saying that he had only ever agreed to a one-week trial at the German team.Despite FC Köln's sporting director Klaus Horstmann threatening to take the matter to FIFA in order for him to fulfil his obligations to his side, Okonkwo says he did not breach any rules in moving to Switzerland.