The presidential frontrunner is a former army chief, who oversaw a brutal crackdown on Morsi's supporters after toppling him.
Lauded by millions for ousting the Islamist leader, Sisi also has sparked fears that Egypt could fall back into autocracy worse than under Hosni Mubarak who was ousted by a popular uprising in 2011.
But the 59-year-old is so sure of his victory that he has not even unveiled his election programme.
During campaigning, he did not attend a single public rally, preferring instead to talk through television interviews in which he insisted that "national security" takes precedence over democratic freedoms.
It could take "20 to 25 years to achieve true democracy," he told Egyptian newspaper editors.
A police crackdown against Morsi supporters has killed more than 1,400 people since July, while over 15,000 have been jailed, and hundreds sentenced to death after speedy trials.
Sisi served as Mubarak's military intelligence chief, the youngest officer to hold the post, and was promoted by Morsi to defence minister.
His supporters see him as a tough leader able to restore stability and kick-start an economic recovery after years of unrest.
They also consider him as a pious and humble man, who addresses his supporters in colloquial rather than classical Arabic.
An aide told AFP that Sisi prays five times a day in accordance with Islamic practice. He often invokes religious sentiments in his speeches.
His opponents in Morsi's Muslim Brotherhood despise him and have compared him to a pharaoh and to villains of Islamic lore.
A father of four, Sisi was born in 1954 near the Hussein mosque, a pilgrimage site in Cairo's old city, and entered the military academy in 1977.
Hamdeen Sabbahi: veteran dissident
A leftist politician, Sabbahi's defeat in the election is almost a forgone conclusion.
The 60-year-old, who says he was jailed 17 times under former presidents Anwar Sadat and Mubarak, came third in the 2012 election which Morsi won.
The veteran dissident proudly upholds ideals of the 2011 revolution and frequently invokes the slogans of "bread, freedom and social justice" chanted by millions when Mubarak was ousted.
A journalist by training, Sabbahi is founder of Al-Karama (Dignity) party, which was refused registration under Mubarak's regime.
He fears a return to authoritarian rule amid the crackdown on Morsi supporters.
Unlike Sisi, the white-haired Sabbahi tirelessly criss-crossed Egypt to showcase his policies, posing as an heir to Gamal Abdel Nasser, the charismatic officer turned president who championed pan-Arabism.
"We toppled two presidents but Egypt is still not calm," he told AFP.
"And it will not calm down unless it becomes a (democratic) state. For this to happen it is necessary to have a candidate who represents the revolutionary goals, which is what we are doing."
Sabbahi is married and the father of two.