Monday's vote marked the 46th attempt by Lebanon's parliament to elect a president.
The country's presidential post had been vacant for more than two years since Michel Suleiman stepped down from power when his term ended in 2014.
Hezbollah has sent fighters to aid the government of Syrian President Bashar al-Assad, and Aoun's rise to the presidency could increasingly put Lebanon at odds with its Western and Arab allies that have sided with Assad's opponents.
In the end, it took an about-face by former Prime Minister Saad Hariri, Lebanon's Saudi-backed main Sunni leader, who formally endorsed Aoun for president last week - reportedly in exchange for Aoun promising him the position of prime minister.
In the fourth round Aoun won 83 votes. He will nominate the candidate with the greatest support amongst parliamentarians.
"We have to wait and see because this could be a good chapter for Lebanon to resolve its many pressing political issues", Wazne said, adding at the same time that "the devil is in the details to come".
The United States congratulates the people of Lebanon on the election of President Michel Aoun, in accordance with Lebanon's constitution. He served in 1988 as prime minister of an interim military government.
In 1943, Lebanon's Muslims and Christians agreed to distribute the country's three most important political posts between them.
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Aoun sought mutual understanding with different Lebanese factions, and signed the Memorandum of Understanding with Hezbollah Secretary General Sayyed Hasan Nasrallah in February 2006, which contributed to the protection of Lebanon in several political and security situations.
Aoun has a wide support base, mostly among Lebanon's educated youth, but is a divisive figure in Lebanon for his role in the 1975-90 civil war.
"(Aoun's election) also politically legitimizes Hezbollah as a nationalist group with cross-sectarian support - a landmark moment for an organization that had largely been defined by its sectarian origins", reported Martin Chulov, a writer for The Guardian.
Caretaker Minister of Telecommunications, Butros Harb said on Tuesday that everybody must cooperate with the newly elected president General Michel Aoun for the sake of Lebanon's best interest.
Supporters of Michel Aoun celebrate his election as president on Monday.
With new leadership, Lebanon will be expected to launch parliamentary elections, which are more than three years overdue, Salem said.
Late in 2015, head of the Lebanese Forces Samir Geagea made a sharp turn and withdrew from the presidential race and announced an agreement with Aoun to back his candidacy. The atmosphere in Jdeideh outside Beirut was one of untrammelled joy, with thousands honking vehicle horns and popping bottles of champagne.
He is expected to nominate Saad Hariri to return as prime minister, but with little consensus in the political landscape, the process of forming a government is likely to be long and arduous.