Rotimi was born to an Ijaw mother and a Yoruba father, and cultural diversity was a frequent theme in his work. Educated in Nigeria in Port Harcourt and Lagos, he traveled to the United States in 1959 to study at Boston University. After receiving a B.A. in fine arts in 1963, he attended the Yale School of Drama (M.A., 1966), concentrating on playwrighting. Upon returning to Nigeria in the 1960s, he taught at the Universities of Ife (now Obafemi Awolowo University) and Port Harcourt. Owing, in part, to political conditions in Nigeria, Rotimi spent much of the 1990s living in the Caribbean and the United States, where he taught at Macalester College in St. Paul, Minnesota. In 2000 he returned to Ile-Ife, joining the faculty of Obafemi Awolowo University.

Rotimi often examined Nigeria’s history and ethnic traditions in his works. His first plays To Stir the God of Iron (produced 1963) and Our Husband Has Gone Mad Again (produced 1966; published 1977) were staged at the drama schools of Boston University and Yale, respectively. His later dramas include The Gods Are Not to Blame (produced 1968; published 1971), a retelling of the Oedipus myth in imagistic blank verse; Kurunmi and the Prodigal (produced 1969; published as Kurunmi, 1971), written for the second Ife Festival of Arts; Ovonramwen Nogbaisi (produced 1971; published 1974), about the last ruler of the Benin empire; and Holding Talks (1979). Later plays, such as If: A Tragedy of the Ruled (1983) and Hopes of the Living Dead (1988), premiered at the University of Port Harcourt. The radio play Everyone His/Her Own Problem was broadcast in 1987. His book African Dramatic Literature: To Be or to Become? was published in 1991.