Alagoa worked at the
National Archives of Nigeria, Ibadan from 1959 to 1962 rising to the rank of a senior archivist. He was a senior research fellow at the Institute of African Studies at the
University of Ibadan from 1967 to 1972. Alagoa worked at the
University of Port Harcourt, as the dean of School of Humanities from 1977 to 1980 and the deputy vice chancellor from 1980 to 1981. He served briefly as the vice chancellor of the university in 1982. Alagoa was a visiting scholar at
Frobenius Institute in 1989, a
Bellagio Study and Conference Center resident scholar in 1990; and a
Brown University research scholar from 1993 to 1994. He was made the pro-
chancellor of
Niger Delta University in 2001. == Personal life ==