CAIRO — When Egypt’s first freely elected president, Mohamed Morsi, named Gen. Abdul-Fattah el-Sisi defense minister, the officer pledged to keep the military out of politics and make way for civilian democracy.

A year later, General Sisi ousted Mr. Morsi, insisting the military was answering the people’s call to secure “their revolution.” Just three weeks later, he once again said he was turning to the people when he urged them to take to the streets to give him a personal “mandate” to crush Mr. Morsi’s base of support in the Muslim Brotherhood.

Then on Monday, Field Marshal Sisi — he added the title the same day — took the first formal step to become Egypt’s next president, insisting he was yielding once again to “the free choice of the masses” and “the call of duty.” With that, he paved the way for Egypt to return to the kind of military-backed governance that was supposed to end with the Arab Spring of 2011.

In his two years in public life as defense minister and then de facto ruler, Field Marshal Sisi has combined the cunning of a spymaster with the touch of a born politician to develop an extraordinary combination of power and popularity not seen here since Col. Gamal Abdel Nasser ended the British-backed monarchy six decades ago.