The 75-year-old has circled the summits of public life for most of his career as a top civil servant, a vice-president, and a prominent businessman, making his fortune in the oil sector and giving some of it away to charity.
But the highest office in the land has eluded him, and in February 2023 he goes again, offering his credentials as a seasoned political operator and serial entrepreneur as the remedy for Nigeria's ills.
Africa's most populous country is facing soaring unemployment, widespread insecurity, high inflation, and a sluggish economy heavily dependent on fluctuating oil revenues.
Mr Abubakar's campaign is built on his success as vice-president between 1999 and 2007, where as head of the government's economic team he oversaw successful reforms in the telecommunications, pensions and banking sectors that led to jobs and GDP growth.
However, his critics point to accusations of financial impropriety against him which they say make him unsuitable for the top office in a country where corruption is a huge challenge.
He is accused of cronyism, especially when he oversaw the privatization of key government assets. He denies any wrongdoing and says the charges are politically motivated.
Mr Abubakar will be hoping to unite the fractured opposition Peoples Democratic Party (PDP), where cracks have emerged since his victory at the primary in June.
Some influential southern governors begrudge his emergence, saying it was the turn of the south to produce Nigeria's next president after eight years of President Muhammadu Buhari, a northerner like Mr Abubakar.