At the beginning of this year, Saad Hariri enjoyed relative anonymity as a business tycoon running his family's hugely-successful empire.
Saad Hariri acknowledges he has a tough job ahead
But everything changed when a massive car bomb killed his father Rafik, the former Prime Minister, in Beirut on 14 February.
The 35-year-old, with no previous political experience, was suddenly propelled into the spotlight as his father's successor.
He admits it was not a job he wanted at first. "Then we decided that what my father wanted to achieve had not been achieved," he said in an interview with Newsweek magazine earlier this month.
Now his Future Current movement, the main anti-Syrian alliance, looks set to have won the election - which puts him in a position to take up the job of prime minister.
He told Newsweek that if elected he wanted to end corruption and boost the economy, as well as free Lebanon from the influence of Syria.
"We have to understand that we come out of 30 years of not making decisions by ourselves, of having a country telling us what to do," he said.
Inexperience 'an advantage'
But he acknowledges he has an uphill task as a newcomer to politics.
"I think I am merely a symbol for now," he told the AFP news agency. "I need to work hard in the coming four years to ... fill a little bit my father's shoes."
Rafik Hariri was an influential figure in Lebanese politics
Saad Hariri, married with two young children, is a business graduate from Georgetown University in Washington.
He took over the family business at just 26 and headed his father's Saudi-based construction firm, Saudi Oger - one of the Middle East's largest firms with a turnover of more than $2bn and a 35,000-strong workforce.
He also managed the Hariri empire's other interests, which include banking, real estate and media. His own real estate firm is said to be worth around $145m.
Lebanon's Daily Star says Saad Hariri's inexperience "in walking the crooked paths of the Lebanese political environment" may work to his advantage.
"Because of his lack of exposure to the corrupt reality of the Lebanese state, he has the means to resist negative aspects of governance that are so prevalent here," the newspaper wrote in early May.