In an official ceremony on Wednesday, Syrian President Bashar al-Assad formally accepted the credentials of U.S. Ambassador Robert Ford, Syria's state news agency, SANA, reported.
Syrian Foreign Minister Walid al-Moallem and Minister of Presidential Affairs Mansour Azzam also attended the ceremony.
Following the formalities, Assad spoke with Ford, wishing him success in his new position.
Ford takes up his duties just days after Lebanese parliamentarians chose Najib Mikati to replace former Prime Minister Sa'ad Hariri, whose government collapsed two weeks ago when Hezbollah and its allies pulled out of the coalition.
The walkout occurred because of Hariri's refusal to sever ties with the U.N.-backed Special Tribunal on Lebanon and its yet-to-be publicized indictments of Hezbollah members in the 2005 assassination of former premier Rafik Hariri, Sa'ad's father.
Miqati, a 55-year-old telecommunications billionaire who maintains close ties with Assad, began assembling his new government on Wednesday.
Ford is the first U.S. ambassador to Syria since former President George W. Bush recalled Margaret Scobey in 2005 following Hariri's assassination and implications that Syria was connected with his murder.
Outrage over Hariri's death forced Syria to withdraw 15,000 troops that had been deployed in Lebanon for more than a decade.