Mohamed Morsi, sworn in on Saturday as Egypt's first civilian and democratically elected president, is also the first Islamist head of state in the Arab world's most populous nation.
Formerly a leader of the powerful Muslim Brotherhood from which he stood down after being elected, Morsi has pledged that under his leadership Egypt will be inclusive.
In a rousing speech on the eve of his inauguration to tens of thousands of jubilant supporters thronging the revolution hub of Tahrir Square, he was careful to reach out to the Christian minority of some 10 percent.
He promised a "civilian state" in an address to "the free world, Arabs, Muslims... the Muslims of Egypt, Christians of Egypt."
The retiring, bearded and bespectacled Morsi has vowed to uphold the goals of the revolution that ousted president Hosni Mubarak last year and to share power with other parties.
However, the ruling Supreme Council of the Armed Forces (SCAF) has sought to defang the post by granting itself sweeping powers.
On Friday a defiant Morsi, whose predecessors as president have all been generals, threw down the gauntlet to the SCAF.
"You are the source of power and legitimacy... there is no place for anyone or any institution... above this will," he said, addressing the people directly. "I renounce none of the prerogatives of president."
Morsi became the Brotherhood's candidate only after its first choice Khairat El-Shater was disqualified. He beat Ahmed Shafiq, Mubarak's last premier, with 51.73 percent of the vote.
Many had written Morsi off as an uncharismatic substitute, saying he would be unable to muster widespread support.
But the powerful Brotherhood mobilised its formidable resources and supporters behind Morsi, who was appointed last year to head its political arm, the Freedom and Justice Party.
He has pledged an inclusive presidential institution that "includes all forces, presidential candidates, women, Salafis and our Coptic brothers," and to end "discrimination against any Egyptian based on religion, ethnicity or gender."
Morsi, who quickly claimed victory hours after polling in the second round of the election closed on June 17, has long held that Egyptians would not vote for a symbol of the old regime.
"Egyptians will never bring back Mubarak through the window after they kicked him out of the door," he had told reporters.
During his election campaign, Morsi offered a fiery stump speech, promising a presidency that would be based on Islam but would not be a theocracy.
Initially awkward, he appeared to gain confidence as campaigning progressed, growing more comfortable in his new role as a potential head of state as he gave interviews and made speeches.
Born in the Nile Delta province of Sharqiya, Morsi graduated with an engineering degree from Cairo University in 1975. He received a PhD from the University of Southern California, where he was an assistant professor, in 1982.
He was a member of an anti-Israel group, the Committee to Resist Zionism, but dedicated much of his time to the Muslim Brotherhood, which first fielded him in a parliamentary election in 2000.
In a 2005 election, which gave the Brotherhood one fifth of the seats in parliament, he kept his seat. But he was soon arrested and jailed for seven months after taking part in protests supporting reformist judges.
By the 2010 election, Mursi had become a spokesman for the Islamists and a member of their politburo.
He was jailed again on the morning of January 28, 2011, a day after the Brotherhood announced it would join the protests that would topple president Mubarak almost two weeks later.
Morsi and other Brotherhood leaders arrested at the time served only a few days before being sprung from jail in massive prison breaks across the country.
The Brotherhood believes in establishing an Islamic state gradually and through peaceful means, but Morsi's focus has been mostly on issues affecting the majority of Egyptians since the revolt, such as the deteriorating economy.
Morsi is married, with five children and three grandchildren.