Born and brought up in Kingston upon Thames, Okonkwo is of Nigerian descent. He attended Tolworth Infants/Juniors School and Southborough High School in Kingston, and later turned down a number of places at the UK's leading drama schools in order to pursue a university education, gaining a First Class degree in Business Computing from the University of Surrey, graduating in 2003. After completing his studies Okonkwo pursued an acting career full-time.