Prof Onyido obtained his B.Sc. in 1974 and PhD in 1979 from the University of Ibadan. He then joined the faculty at Ibadan as lecturer, then became a Senior lecturer, after which, he moved to the University of Agriculture of Makurdi (Nigeria) becoming full professor in 1990.
His research interests focus on the reactivity and mechanism(s) of catalysis in three main areas which are aromatic nucleophilic substitution and δ-complex formation, isotopic hydrogen exchange in molecules of biological importance and mechanisms of abiotic degradation of organophosphorus pesticides and model compounds. He has served at the University of Agriculture of Makurdi as Head of the Department of Chemistry, Dean of the College of Science Agricultural and Science Education, Deputy Vice-Chancellor and Director of the Centre for Agrochemical Technology.
He has introduced the Postgraduate Degree Programs of Environmental Science and Agrochemical Technology in the curriculum of the University. He also served as Expert of the National Universities Commission fashioning science graduates for a competitive trans-national economy. He has represented Africa at the CHEMRAWN (Chemical Research applied to World Needs) Committee of the International Union of pure Applied Chemistry (IUPAC).
He is member of the World Innovation Foundation, Chemical Society of Nigeria, American Chemical Society and several other professional societies also; has several national, regional and international recognition and awards. He has 44 publications and 1 book.