From 1989 through 1991, Adesina was engaged as a teaching assistant at the Obafemi Awolowo University, Ile-Ife (1989–91), and a Lecturer Grade III at the Adeyemi College of Education, Ondo, Nigeria from 1991 to 1993.
He joined the faculty of the Department of History, University of Ibadan, in 1993, rising to the rank of full professor in 2007.
In 1994, Adesina was a Grantee of the United States Information Agency at the Boston College, Massachusetts.
He has also received several distinguished visiting fellowship awards, including the Fellowship of Salzburg Seminar, Austria (2001); Fellow of the Atlantic History, Charles Warren Center, Harvard University (1998); the African Visiting Fellow, Rhodes Chair of Race Relations, St Antony's College, Oxford (2004/2005); and, Fellow of the Institute of Advanced Studies, Jawaharlal Nehru University, New Delhi (2009).
[7] In May 2017, Adesina was elected as president of the Society of Nigerian Archivists, taking over from Gabriel Alegbeleye.