Born into poverty, at the age of six he was kidnapped and forced to join the National Resistance Army and consequently did not see his family for five years.

He made the Ugandan national boxing team and was selected to fight at the 1996 Summer Olympics in Atlanta, Georgia, but did not attend due to financial difficulties.

On a Ugandan national amateur team trip to the United States, Ouma decided to stay to undertake a career as a professional boxer to support his family in Uganda.

Since the Karmazin bout, Ouma has remained active in the Light Middleweight division, earning three wins, two by knockout.

Ouma returned to the ring with an impressive win over undefeated fellow southpaw Sechew Powell August 5, 2006.

On September 25, 2010, Ouma stopped Joey Gilbert in the 6th round of their 10-round bout for the vacant NABA middleweight title at the Grand Sierra Resort in Reno, Nevada.