A Professor of Mechanical Engineering at the Department of Mechanical Engineering, Covenant University. He has a Ph. D in Mechanical Engineering (Energy Systems and Production Technology).

He has over one hundred and seventy (170) scholarly publications in high impact international journals, conference proceedings and chapters in reputable books indexed in the Scopus ® and Thompson Reuters ® ISI. His research's visibility garnered more than 1233 citations with h-index 20 in Scopus and over 2263 citations, h-index 25, and i10-index 66 in Google Scholar. He is equally a reviewer for some of the top-rated, high impact international journals which include Energy, the international journal and Renewable and Sustainable Energy Reviews.

His research interests span across two major fields of Mechanical Engineering which are Energy Systems and Production (or Manufacturing) Technology. Based on these interests, his major contributions are hinged on five thematic areas – Renewable Energy and Low Carbon Development, Environment Induced Failure of materials for design technology, Fatigue and Failure Analyses of materials for design technology, Machining and Production Technology, and the Application of nanoparticles and nanofluids to Energy Systems and their influence on Energy Saving Technology. His current research focus is on flow dynamics around the wind turbine blade.

Professionally, Prof. Oluseyi O. Ajayi is a recipient of some local and international awards and recognitions, some of which include: Chancellor's honours research award for outstanding research output, 2017, 2018, 2019, 2020, recipient of the British Academy's Global Challenges Research Fund 2019, recipient of the U.S. Govt's Fulbright Senior African Research Scholar Programme, 2019, Best Mechanical Engineering Department lecturer, 2018/2019 academic session, top ten (10) researcher in Covenant University since 2010.

He is currently serving as an external examiner and assessor to some universities/institutions, some of which include: Tshwane University of Technology, Pretoria, South Africa, University of Johannesburg, South Africa, National Research Foundation, South Africa, University of Nigeria, Nsukka and Afe Babalola University, Ado Ekiti.