Widely credited with reshaping Nigeria’s commercial hub Lagos, Mr Tinubu saw off a divided opposition party and a youth-backed third-party candidate in February’s election.
Defeated candidates Atiku Abubakar and Peter Obi are challenging his victory in court, alleging the result was manipulated.
Mr Tinubu has rejected the allegation, and has hailed the peaceful transfer of power as “our enduring faith in representative government”.
He has replaced Muhammadu Buhari, who has stepped down at the end of his two terms.
Africa’s most populous country is facing a troubled economy, widespread insecurity and high inflation. Many will want Mr Tinubu to hit the ground running when he takes on one of Africa’s most daunting jobs.
Once forced into exile by military ruler Sani Abacha, Mr Tinubu knows the value of freedom and wears it as an insignia on his signature hat – a broken shackle that looks like a horizontal figure of eight.
A trained accountant, it was the activities of the pro-democracy National Democratic Coalition (Nadeco) group, where he was a member, that brought him into Abacha’s crosshairs.
The opposition of groups like Nadeco, and Abacha’s death in 1998, ushered in Nigeria’s democracy in 1999 and in many ways, Mr Tinubu, a former Mobil oil executive, feels entitled to Nigeria’s presidency.
Mr Tinubu – known to his supporters as “Jagaban”, which translates to “leader of warriors”, a title from the Emir of Borgu in Niger state – will now be looking at unifying a country that is retreating into regional lines and religious blocs, as the election results showed.
But it is not a job that fazes him. He has pointed to his time as Lagos state governor between 1999 and 2007 to sell his candidacy to Nigerians.
Under his tenure, Lagos massively grew its income through huge foreign investment, while a public transport scheme that saw new lanes created for rapid buses eased the notorious traffic jams faced daily by commuters.
But the city of around 25 million people has not lived up to its reputation as a megacity despite his claims of turning it around.
Public infrastructure is largely in a state of disrepair – basic amenities such as water and public housing are decrepit, while a light rail project started during his tenure has not been completed almost 20 years later despite the riches of the state.
He has also been accused of keeping a grip on state finances despite leaving office in 2007.
Every governor that has succeeded him has been a protégé following a “grand roadmap”, while one that dared to find his own path was quickly brought to heel, aided by powerful transport union members.
There are also allegations of corruption against Mr Tinubu, which he denies.
Two years ago, Dapo Apara, an accountant at Alpha-beta, a firm where Mr Tinubu purportedly holds stakes through a crony, accused him of using the firm for money laundering, fraud, tax evasion and other corrupt practices.
Mr Tinubu was sued despite him and Alpha-beta denying the allegations but all parties decided to settle out of court last June.
Such allegations, including twice facing Nigeria’s Code of Conduct Tribunal (CCT), on allegations of breaching the code of public officers – where he was cleared – make opponents say Mr Tinubu is not the right man for the job in a country where corruption is high.
In the previous election, a brazen display of an armoured van used by banks to move money driving into his palatial compound in the Ikoyi area of Lagos fuelled suspicions that he was involved in vote-buying, which he made no great effort to deny.
“If I have money, if I like, I give it to the people free of charge, as long as [it’s] not to buy votes,” he said.