The appointment of a civilian prime minister was a major condition imposed by the West African regional economic bloc, Ecowas, on Mali to lift sanctions that were imposed after an August 18 coup.
Ecowas had closed borders to Mali and stopped financial flows to put pressure on the junta to quickly return to a civilian government.
Former defence minister and retired Col Maj Bah N’Daw was inducted on Friday as the new transitional president, while Col Assimi Goita, head of the junta that staged the coup, was installed as Mali’s new vice president.
The three government heads are to lead the transitional government to an election in 18 months.
The appointment of Mr Ouane, 64, was made by official decree Sunday and signed by Mr N’Daw.
Mr Ouane was minister of foreign affairs from 2004 to 2011 under former president Amadou Toumani Toure.
He also served as Mali’s permanent representative to the United Nations from 1995 to 2002 and later as a diplomatic adviser to Ecowas.
The junta, which calls itself the National Committee for the Salvation of the People, deposed president Ibrahim Boubacar Keita in August, detaining him, the prime minister and other government officials.
Mr Keita, who became ill, was eventually released and has gone to the United Arab Emirates for treatment.
Ecowas became involved in negotiations that have pressed for a quick return to civilian rule.
UN officials have called for the release of the 13 of the 18 detained officials still being held at the Kati military camp in the Malian capital of Bamako.
There has been widespread concern that the upheaval in Mali will set back efforts to contain the country’s growing Islamic insurgency.
After a similar coup in 2012, Islamic extremists grabbed control of major towns in northern Mali.
Only a 2013 military intervention led by France pushed extremists out of those towns and the international community has spent seven years battling the militants.
