career diplomat Michel Kafando as Burkina Faso's interim president following the ousting of its veteran leader.
AU chief Nkosazana Dlamini-Zuma praised the people of the west African state "for their political maturity and sense of responsibility", and called for "a smooth transition under the direction of civil authorities".
The appointment of the former foreign minister and UN ambassador is set to end weeks of uncertainty in the impoverished country after mass protests toppled the 27-year regime of president Blaise Compaore and the military seized power.
The naming of the interim leader came ahead of a two-week deadline the AU had given the country's army to return the state to civilian rule.
Dlamini-Zuma said she "welcomes the restoration of the constitution" and the "significant progress" made towards civilian rule, repeating the AU's committment and support to the country.
The 54-member bloc also called on the international community to support efforts to "deepen democracy" in the country.
Kafando, who will have to be confirmed by the Constitutional Council, previously served as the country's ambassador to the United Nations from 1998 to 2011. He was also Burkina Faso's foreign affairs minister between 1981 and 1982.
Mass unrest erupted in Burkina Faso in late October over ex-president Blaise Compaore's bid to change the constitution, which would have allowed him to extend his 27-year rule of the landlocked former French colony.