Adly Monsour was sworn in Thursday at the Constitutional Court in a ceremony broadcast live on state television.
According to military decree, Mansour will serve as Egypt’s interim leader until a new president is elected. A date for that vote has yet to be set.
Manosur’s assumption of office comes a day after the military deposed Morsi, who took office a year ago as Egypt’s first democratically elected president.
The military moved to oust Morsi after millions of Egyptians took to the streets this week to demand his resignation.
Morsi is under house arrest at an undisclosed location.