Olayinka's research career started during his residency training in Community Health at the University College Hospital, Ibadan. He participated and also led researches on communicable and non-communicable diseases prevention and control, health economics and infectious disease epidemiology during his residency training. He was the best fellowship candidate in the Faculty of Community Health, West African College of Physicians in 2013.
He has worked for the Federal Medical Centre, Owo, Ondo State Nigeria as a Consultant Community Health Physician, African Field Epidemiology Network as a Field Coordinator and Yale School of Medicine as a Postdoctoral Associate. He won a meritorious service award from His Excellency Dr Ernest Bai Koroma Executive president of Republic of Sierra Leone for his outstanding contributions to Ebola Virus Disease response in 2015. He is a clinical epidemiologist with the College of Medicine, University of Ibadan. He has a special interest in infectious diseases, tobacco control and global health. He is passionate about generating new knowledge and solving existing infectious diseases and global health problems.
National Youth Service Corps (NYSC) honours award, 2006, Meritorious service award from His Excellency Dr Ernest Bai Koroma Executive president of the Republic of Sierra Leone for his outstanding contributions to Ebola Virus Disease response, May 2015