If it was his time as finance minister that has earned Niinistoe widespread respect and credibility, it may also be the turbulent events in his life that could help him win votes in Finland's second round of presidential poll on Sunday.
The conservative veteran politician lost his wife of more than 20 years and the mother of his two sons in 1995 to a tragic road accident.
Nine years later, he narrowly escaped the tsunami in Thailand by climbing a tree with his younger son.
Before remarrying in 2009 his party's spokeswoman 29 years his junior, Niinistoe was engaged to an ex-beauty queen turned parliamentarian, although that relationship ended a year after the engagement.
Beyond the personal drama, Niinistoe had earned credibility through his role in pulling Finland from the abyss of recession in the 1990s.
"It was one of the high points of his political career and people remember him fondly for this," Turku University parliamentary researcher Ville Pernaa said.
Helsinki University political science professor Tuomo Martikainen agreed, pointing out that for many Finns, "Niinistoe represents practical economic expertise."
Th presidential campaign set against the backdrop of the eurozone crisis, has focused on Niinistoe's unwavering support for the common currency, which was introduced in Finland while he was finance minister from 1996 to 2003.
The avid rollerskater's broad political experience -- as not just finance minister but also justice minister and deputy prime minister -- has also won him endorsements from most of the candidates who did not make it to the second round.
According to the most recent opinion poll, he has a broad support of 64 percent, nearly twice that of his Greens contender Pekka Haavisto.
Described by some as impatient and rude and by others as honest and forthright, Niinistoe may however have a shortcoming in foreign policy.
"The role of the president calls for relations with the wider world," Jan Sundberg, a Helsinki University political science professor, told AFP.
But Niinistoe lacked experience in "areas relating to the environment, developing countries or Asian economies," said the professor.
The last of four children born to working class parents in southwestern Finland, the 63-year-old earned his law degree at Turku University.