Ibrahim Boubacar Keita, universally known as IBK, served as Mali's prime minister from 1994 to 2000 before heading the country's National Assembly for five years assuming this role in 2002.
Keïta was born in Koutiala in central Mali and was educated at Paris's Sorbonne University and Lycée Askia-Mohamed in Bamako, the Malian capital.
He holds degrees in history, political science and international relations.
After completing his studies, Keita worked as a researcher at the National Centre for Scientific Research (known in French as Centre National de la Recherche Scientifique - CNRS), a public organisation under the responsibility of the French ministry of higher education and research.
Keita returned to Mali in 1986 and worked as a technical consultant for the European Development Fund, launching the first small-scale development programme for the European Union's aid activities in Mali.
In the July 28 elections he won the first round with nearly 40 percent of the vote and remains the political heavyweight in the race, having secured the endorsement of 22 of the 25 first-round losing candidates.
Model of democracy
IBK has campaigned on pledges to restore Mali's honour as a model for democracy in West Africa where political instability is still a problem.
Having stood up to strikes and student protests when he was prime minister, he has a reputation for firmness that many Malians believe is needed to restore the rule of law across the divided nation.
A nationalist with a popular touch, Keita has avoided strongly criticising the leaders of a March 2012 coup which overthrew former President Amadou Toumani Toure, amid widespread frustration at his government's corruption and failure to tackle poverty.
He withdrew his RPM party from an anti-junta coalition in May 2012, saying that the handling of the Mali crisis had infringed upon national sovereignty.
He has pledged "zero tolerance' for corruption - echoing the words of coup leader Captain Amadou Sanogo.
A founding member of the AD"MA party, historically Mali's largest, Keita befriended Alpha Oumar Konare, who was elected president after Traore was toppled in a 1991 coup.
Konare then promoted him steadily from ambassador to Ivory Coast, to foreign minister and ultimately prime minister.
Keita quit ADEMA to found his own party, finishing third in the 2002 presidential election won by Toure, the president who was toppled a decade later.
Peace deal opponent
IBK has been an outspoken opponent of a 2006 peace deal with Tuareg separatists that partly demilitarised northern Mali, which critics said contributed to the current crisis.
He was Toure's main opponent in the 2007 elections, winning 19 percent of the vote.
For almost two decades, Ibrahim Boubacar Keita was part of the political elite in Mali. He tried to become president twice, but without success. As he is now 68 years old, this Sunday's run-off election is expected to be his last attempt.
IBK is also well connected in the donor community.
"He is known throughout the donor community and always maintained a dialogue with us, even when he didn't hold any position," according to Richard Zink, head of the delegation of the European Union in Bamako.
This, Zink says, is important for a country whose economy has stagnated since last year's coup. At the last donor conference for Mali in Brussels in May 2013, the EU pledged $691m in financial aid for the years 2013 and 2014. The money is desperately needed for the country to get back on its feet again.