Macky Sall is set to become the next president of Senegal after defeating his political mentor Abdoulaye Wade in a runoff election Sunday.

Mr. Sall was a staunch supporter of Mr. Wade's opposition Senegalese Democratic Party when it defeated the ruling Socialists in 2000, bringing Mr. Wade to power.

He went to serve as Mr. Wade's minister of interior and mining before being picked to serve as prime minister from 2004 to 2007.

In 2007, he successfully led Mr. Wade's re-election campaign. He lost his job as prime minister but went on to become president of the National Assembly.

It was during his tenure as the head of the National Assembly that Mr. Sall made what he says on his website was perceived as a “heavy political mistake:” He dared to summon Mr. Wade's son, Karim, before the National Assembly for questioning over financial irregularities.

Soon after, Mr. Sall quit the PDS and the National Assembly. He went on to found his own party, the Alliance for the Republic, under which he was elected mayor of his hometown of Fatick.

Mr. Sall was one of 13 opposition candidates in the first round of the presidential election, which Mr. Wade won with 35 percent of the vote. The losing candidates turned their support to Mr. Sall, who promised to reform the government and lower basic food costs.

At 85 years of age, Mr. Wade is Africa's second oldest leader. Mr. Sall is more than three decades his junior.