He was the first civilian governor of Abia State and was the minister of science, technology and innovation of Nigeria from November 2015 until his resignation in 2022.

[3] He also sat for the Higher School Certificate Examination at College of Immaculate Conception (C.I.C) Enugu, graduating as the overall best student.

[6] After his graduation from the University of Lagos, Ogbonnaya Onu became a teacher at St. Augustine's Seminary, Ezzamgbo, Ebonyi State.

He also served as the acting dean of the Faculty of Engineering and was also elected as a member of the Governing Council of the university.<[3] Ogbonnaya Onu started his political career as an aspirant for a senatorial seat in the old Imo State on the platform of the National Party of Nigeria (NPN).<[3] He contested for the position of Governor of Abia State in 1991 under the umbrella of the National Republican Convention and won.

[12] In October 2022, a Nigerian national honour of Commander of the Order of the Niger (CON) was conferred on him by President Muhammadu Buhari.