Government formation ends a 13-month vacuum that saw the Arab country slide deeper into one of the worst crises in its history.
Lebanon's Prime Minister Najib Mikati and President Michel Aoun have signed a decree forming a new government in the presence of parliament speaker Nabih Berri, the presidency said in a statement.
Lebanon has been without a fully empowered government since the catastrophic August 4, 2020 explosion at Beirut port, which forced the resignation of then PM Hassan Diab's government.
Rival political groups had been locked in disagreement over the make-up of a new government since then, hastening the country's economic meltdown.
Mikati, who has been prime minister twice before and is the country's richest man, was designated on July 26 to form a government after his two predecessors threw in the towel.
Lebanon can no longer provide electricity to its citizens for more than a few hours a day, nor can it afford to buy the fuel needed to power generators.
Very few of the international community's demands for a broad programme of reforms have yet been met, hampering the disbursement of foreign assistance.
Further stalling the bankrupt state's recapitalisation has been the government's failure to engage the International Monetary Fund and discuss a fully-fledged rescue plan.