Mohamed Morsi will be sworn in Saturday as Egypt's first democratically-elected president, taking the helm of a deeply divided nation that is economically strapped and lacks a working government.
The ceremony will take place before the Supreme Constitutional Court and will be overseen by Egypt's military rulers who have been in control of the country since Hosni Mubarak was ousted last year during a popular revolution.
Morsi upstaged the ceremony Friday, taking to Cairo's Tahrir Square before thousands and declaring that the people are the source of his authority as president.
"The whole nation is listening to me," he said in the televised address. "There is no authority above the authority of the people."
Morsi's speech appeared aimed at Egypt's ruling military council, whose recent actions have raised concerns about whether it would fully hand over control to an elected government.
Egypt's electoral commission declared Morsi the president-elect Sunday after a runoff with Ahmed Shafik, a former air force general who served as Mubarak's last prime minister.
Just days before the election, a high court ruled that Egypt's parliament was unconstitutional.
Morsi's supporters -- primarily the Muslim Brotherhood -- are pushing for a confrontation with the generals, who following the court ruling ordered the Islamist-dominated parliament dissolved and announced they would retain legislative power for an indefinite time.
Morsi leads the Freedom and Justice Party, the political arm of the Muslim Brotherhood.
Egypt's oldest and best-organized political movement, the Brotherhood won the largest share of seats in parliamentary elections this year.
World leaders, meanwhile, will likely be watching what Morsi does next.
During the speech Friday, he said he would work to free the blind Egyptian cleric serving a life sentence in the United States for a conspiracy conviction related to the 1993 World Trade Center bombing.
He said he wanted to work to free political prisoners, which he said included Sheikh Omar Abdel-Rahman.
"Their rights will be on my shoulders and I won't spare effort" to free them, he said.
Morsi is a study in contrasts: a strict Islamist educated in Southern California who vowed during his campaign to stand for women's rights yet argued for banning them from the presidency.
During the historic campaign, Morsi said he would support democracy, women's rights and peaceful relations with Israel if he won.
But he has also called Israeli leaders "vampires" and "killers."
Morsi focused his campaign on appealing to the broadest possible audience after a slogan associated with his campaign, "Islam is the solution," sparked concerns that he could introduce a fundamentalist Islamic theocracy.
During the campaign, he said he had no such plans. His party seeks "an executive branch that represents the people's true will and implements their public interests," Morsi told CNN's Christiane Amanpour.
Asked whether he would maintain Egypt's 1979 accord with Israel, Morsi said, "Yes, of course I will. I will respect it provided the other side keep it up and respect it."
Morsi was not originally his party's pick for the country's top post. He stepped in after the first choice was disqualified. Khairat al-Shater was among three candidates who were told they did not meet candidacy requirements.
The Muslim Brotherhood had originally pledged not to seek the presidency, but the group reversed its decision as the election approached.
Morsi's official biography on the Freedom and Justice Party website describes him as "one of the most prominent political leadership figures of the Brotherhood, the organization that led the struggle against the ousted repressive regime in its last decade."
He led the Brotherhood's parliamentary bloc from 2000 to 2005 in addition to serving as president of the Department of Materials Science, Faculty of Engineering at Zagazig University.