Masoud Fezeshkian, a relatively moderate member of Iran's parliament, was declared Iran's next president on Friday after overwhelmingly defeating his hardline conservative rival in a runoff election.
The 69-year-old replaces Ibrahim Raisi, who died in a helicopter crash last month.
Mr Pesheshkian's mostly young supporters took to the streets of the capital, Tehran, and other cities to celebrate, singing, dancing and waving his campaign's signature green flag even before the final results were announced.
He gave hope to some of the country's younger generation at a time when many were feeling pessimistic about the future. Some were planning to leave the country to find a better life elsewhere.
He has represented Tabriz city in the Iranian parliament since 2008 and previously served as Iran's Minister of Health.
In the 1990s, he lost his wife and one child in a car accident. He never married again and raised his other three children, two sons and a daughter, on his own.
His victory frustrated the plans of the Islamic hardliners, who wanted to replace Raisi with another conservative and, together with Supreme Leader Ayatollah Ali Khamenei, to seize all power in Iran.
At a polling station in Tehran, 48-year-old Fatemeh told AFP she voted for a moderate because, she said, “the rights of women and youth are her priorities.”
“I know Pezekian will be a boiteux president, but he is better than a hardliner president,” Aparin, 37, who runs a beauty salon in Isfahan, told Reuters.
Many voters boycotted the first round of voting last week, angered by Iran's domestic repression and international conflicts that have led to increased sanctions and widespread poverty.
They were also frustrated by the lack of choice in the elections: five of the six candidates allowed to run were hardline Islamists.
And there was a sense of despair that there was little hope for real change, since Ayatollah Khamenei had the final say on government policy.
One of those who refused to vote was Azad, a 35-year-old human resources manager and activist from Tehran who has been jailed twice for criticizing the Iranian government.
Azad, whose name has been changed for his safety, said he was still traumatized from enduring grueling interrogations in solitary confinement.
She told the BBC that regardless of Mr Pezekian's victory, Iran's supreme leader remained a “puppet master”.
She noted that in the 45 years since the Islamic Revolution, “reformists have made no effort to reform the political structure.”
