His political career began in 1998 when, running on the platform of the now defunct United Nigeria Congress Party (UNCP), he contested and won a Senate seat representing the Kebbi Central constituency. The results of the election annulled soon after they were announced. Following the death of military dictator Sani Abacha and a brief period of transition, new elections were held. Aliero, now representing the All People's Party (APP), contested and won the Kebbi State gubernatorial election. He was sworn in on 29 May 1999.