He served in the government and cabinet of Daniel arap Moi, Kenya's second president, for many years.

During this time, he held the post of member of parliament for the Larger Migori constituency (1963 – 1992) and the portfolios of Minister of Energy.

Okwanyo was born in South Nyanza in 1928 and received his early education at Nyamome Primary, Kisii High School between 1946 and 1950 before joining the Medical Training Centre (MTC), Nairobi, where he qualified as a radiographer in 1953.

His mother is Hellen Nyachieo who hails from Waswetta and Father Noah Biko a Jakatiga.

John Okwanyo was a member of the Anti-communist league and he represented Kenya in the 12th conference held in Seoul, Korea.