(Bloomberg) -- Members of Greece’s leftist Syriza party elected Stefanos Kasselakis to head the country’s second-largest political party after the resignation of former leader Alexis Tsipras in June following a free fall in support for his party in two general elections earlier this year. 

With 75% of the votes counted, Kasselakis won 56.7% in a run-off with former Labor Minister Effie Achtsioglou, a party official said Sunday. Neither candidate received more than 50% of the vote in a first round on Sept. 17. The result means Kasselakis, a former associate with Goldman Sachs Group Inc., will lead the opposition even if he hasn’t served in parliament.  

Tsipras, a former prime minister, and his Syriza-led government came to power in 2015 and during the first months of his administration Greece came close to exiting the euro-area. He eventually agreed on new bailout terms imposing further austerity measures that caused him to lose part of his popularity at home. Tsipras remained in power until 2019, when the current premier Kyriakos Mitsotakis took over and Syriza became the country’s main opposition.  

Kasselakis’s announcement in August that he’d seek the party leadership took the political world by surprise, especially as three of the other four candidates were former cabinet ministers in the Tsipras administration. Kasselakis has never held public office and failed to enter parliament after Tsipras nominated him as a so-called state lawmaker. These representatives aren’t elected, but appointed to parliament according to each party’s share of the national vote. Owing to Syriza’s poor showing, only three of the party’s candidates made the cut as state lawmakers. 

Syriza’s new president also becomes the first openly-gay person to lead a Greek political party and has campaigned with his partner, Tyler McBeth, a 32-year-old American nurse. 

“I don’t have a gay agenda. I have a human agenda,” Kasselakis said in a statement in August to announce his candidacy, asking people to vote for him because he has the ability to defeat Mitsotakis.

Kasselakis has positioned himself as a self-made man who wants social equality, the separation of church and state and the abolition of compulsory military service. While acknowledging he has little experience within a political party, he says his life experience will help him take the party on a new path. 

The 35-year-old was born in the affluent northern Athens suburb of Maroussi, and went to the US when he was 14 after getting a full scholarship to the Phillips Academy in Andover, Massachusetts, an exclusive boarding school that was founded shortly after the American Revolution. He studied at the University of Pennsylvania, earning a Batchelor of Science degree in finance and a Batchelor of Arts in international studies. 

While still a student, he worked as a volunteer on the staff of then-Senator Joe Biden during the 2008 presidential campaign. 

In 2009, at age 21, he began working at Goldman Sachs. Far from developing a passion for finance, Kasselakis said he saw first hand “how much arrogance money brings.” Three years later, after securing a loan with a personal guarantee, he began investing in the shipping industry.

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