Prof. Osuji retired voluntarily from Imo State University in 1990 to pursue a career in politics. In 1991, he emerged as the Imo State Governorship candidate of the Social Democratic Party (SDP) with an unprecedented landslide victory.
In 1990, Professor Osuji retired from his position at Imo State University to enter politics.  He was elected as the SDP's gubernatorial candidate in 1991 and secured a decisive win.