Hazem Salah Abu Ismail, a firebrand fundamentalist leader, had a devoted following in the run-up to the 2012 elections before his disqualification.
He had claimed neither of his parents were dual citizens when his mother had acquired US nationality.
The election law banned dual citizens or their children from running for president.
That election was won by another Islamist, Mohamed Morsi, who ruled for only a year before the army toppled him and unleashed a deadly crackdown on Islamists.
