after graduating from kamukunji high school in nairobi, onyango began his professional career at k.r.a. in 2006, who at the time were competing in the now defunct nationwide league, before joining gor mahia two years later. he has been "k'ogalo"'s first-choice keeper since the beginning of the 2009 season, after jacktone odhiambo left the club for ulinzi stars. he captained the side to their first league title in 18 years in 2013.