He served as a Deputy in the National Assembly of Senegal from 1983 to 2004, as Mayor of Rufisque from 1987 to 2002, and as President of the Council of the Republic for Economic and Social Affairs (CRAES) from 2004 to 2007.

Diop was born in Rufisque in 1936[1][3] and joined the Youth Movement of the Senegalese Democratic Bloc in 1954[1][4] as a founding member.

[1] Shortly before the first round of the 2000 presidential election, violence broke out between supporters of the PS and the opposition in Rufisque on 23 February 2000; there were six injuries, and two homes owned by Diop were set on fire.

According to Diop, his defection "dealt a severe political, electoral and psychological blow to the PS and its candidate, Abdou Diouf", who was defeated by Wade in the second round.

However, Diop was unwilling to resign, saying that he had done nothing wrong and that people would not understand if he left his post before the end of his five-year term in August 2009.

On 4 October, when Diop was preparing to travel to a meeting of the Union of Economic and Social Councils and Similar Institutions of La Francophonie, Wade barred him from leaving the country.

[9] Diop said on 16 September 2009 that he did not favor moves to eliminate the two-round system for presidential elections, arguing that it would be less democratic to decide the outcome in a single round.