Lebanon s Prime Minister-designate Najib Mikati speaks following his meeting with the president at the presidential palace in Baabda, east of the capital Beirut, on June 23, 2022. AFP
The 66-year-old billionaire, who had been widely expected to keep his job, secured 54 votes during parliamentary consultations, giving him a clear edge over other potential nominees.
President Michel Aoun subsequently asked him to form a new government, a task analysts fear could take weeks, if not months, despite the economic emergency facing the country.
By convention, Lebanon's prime ministerial position is reserved for a Sunni Muslim, the presidency goes to a Maronite Christian and the post of speaker to a Shiite Muslim.
His nearest rival for the position of prime minister-designate was former ambassador to the United Nations Nawaf Salam, who only received 25 votes.
Most of the deputies in Lebanon's 128-seat parliament chose not to designate any candidate.
The powerful Iran-backed Hezbollah movement, whose political alliance lost the clear majority it had in the previous parliament, threw its weight behind Mikati.
The Tripoli native, who is the richest man in bankrupt Lebanon, has already headed three governments since 2005.
Analysts expect him to struggle to reach a deal for a fourth administration. The current cabinet was formed in September last year after a 13-month wait.