CAIRO, Egypt — He spent time in jail during the Hosni Mubarak regime, but not as long as some fellow Islamists. He is well-educated, having studied at the University of Southern California, yet still betrays his rural roots. He rose through the ranks of the once-banned Muslim Brotherhood as a lacklustre but loyal foot soldier.

Now, Mohammed Morsi has made history in breathtaking fashion, becoming the first Islamist to rise to the presidency of the most populous Arab nation.

Aiming to defuse anxieties among large numbers of Egyptians who fear an Islamic agenda, Morsi said, “I am a president for all Egyptians.”

Morsi also borrowed phrases used by Abu Bakr, the first Muslim ruler after the 7th century death of the Prophet Muhammad, saying, “If I don’t obey God in serving you, you have no commitment to obey me.”

Sunday’s announcement by the country’s electoral commission capped a political standoff that tested the nerves of not just Egyptians but many around the world.

The U.S.-trained engineer who rode some improbable twists and turns in Egypt’s 16-month transition to democracy is an enigma: Despite his education, he sometimes struggles to communicate in public and can be off-putting to some secular elites.

The bespectacled and bearded Morsi squeaked to victory in the freest election in Egypt’s history, and now the 60-year-old university professor must prove his mettle by standing up to the ruling generals who in recent days have stripped the presidency of real power.

For 35 years, Morsi obediently followed the Muslim Brotherhood’s strict rules, abiding by the principle of unquestioned obedience to its supreme leader — a position that changed hands five times during that period and currently is held by Mohammed Badei.

Morsi has dutifully mirrored the group’s strategy of couching a hardline doctrine with short-term pragmatism. In an example that looms large now that he has been elected, Morsi is anti-Israel but he does not call for annulling Egypt’s 1979 peace treaty.