A professional geologist, Omuku held senior positions in Shell Nigeria and Shell UK before his appointment as Shell Nigeria’s chief geologist, and later, Executive Director External Affairs, Director of Shell Trustees Ltd, Chairman, Board of Shell Nigeria Gas, and Senior Advisor, Shell International, London, a position he held until he retired from Shell. He has served as a member of the governing council of Ahmadu Bello University, Zaria, a member of the board of Nigerian Mining Corporation, Chairman of the Rivers State of Nigeria Bureau of Public Procurement, Chairman of the Rivers State (of Nigeria) Sustainable Development Agency, and Archbishop of Canterbury’s Adviser on Anglican Communion Affairs.

Omuku was a member of the Board of Trustees of the Rivers Community Development Foundation (set up by the World Bank), and a member of Friends Life Stewardship Committee of Reference on ethical investment; consecrated a Bishop of South Sudan and Sudan, he is an Assistant Bishop in the Diocese of Southwark, Church of England, the Archbishop of Canterbury’s Special Representative on Conflict in sub-Saharan Africa, and chairman Alluvial Trade Advisory Board.