When Tinubu joined the Social Democratic Party in 1991, his political career officially began. During the brief Nigerian Third Republic, he was elected to the Senate in 1992 and served as the representative for Lagos West. Tinubu was a founding member of the pro-democracy National Democratic Coalition, which organized support for the restoration of democracy and the acknowledgement of Moshood Abiola as the election’s victor after the results of the June 12, 1993, presidential election were declared invalid.
Following the overthrow of General Sani Abacha as military head of state, Tinubu fled the nation in 1994 and returned in 1998, marking the beginning of the Fourth Nigerian Republic upon the passing of General Sani Abacha.
Bola Tinubu was a protégé of Abraham Adesanya and Ayo Adebanjo, the leaders of the Alliance for Democracy (AD), in the lead-up to the 1999 elections. He defeated former Works and Housing Minister Wahab Dosunmu and Funsho Williams to win the AD primary for the Lagos State governorship elections.
On the AD ticket, he ran for governor of Lagos State in January 1999 and won the election.