Greenblatt, 43, will succeed Abraham Foxman, who announced in February that he would be stepping down effective July 2015. Foxman, 74, has been the ADL’s national director since 1987.

The news was first reported by JTA on Thursday and followed shortly afterward by a formal announcement at the ADL’s annual meeting in Los Angeles.

The ADL said the unanimous selection of Greenblatt by the 16-member succession committee was the culmination of a two-year nationwide search led by the Atlanta-based executive search firm BoardWalk Consulting. The firm reviewed hundreds of prospective candidates from the fields of business, law, academic and nonprofit management, according to an ADL news release.

Greenblatt, a grandson of a Holocaust survivor who escaped Nazi Germany but lost nearly all his family in the war,  interned for the ADL while in college at Tufts University and later participated in an ADL professional leadership program.

His wife, Marjan Keypour Greenblatt, an Iranian-American Jewish immigrant, worked as an associate director at ADL’s Los Angeles office for about eight years. Until last December, she was acting director of the Israel on Campus Coalition. She went on to co-found the new nonprofit Alliance for Rights of All Minorities, which promotes women’s and minority rights in Iran, and serves as its director.

“Marjan herself escaped from her native Iran after the Islamic Revolution when this ancient country that once championed tolerance instead forged a political ideology in the toxin of anti-Semitism,” Greenblatt said Thursday in a speech delivered after the announcement, according to a transcript of remarks provided by the ADL. “Like my grandfather decades earlier, my wife had to flee the land of her birth and came to this country with the help of HIAS as a political refugee because of her Jewish identity. And so our lives and those of our children are shaped by this pernicious force, this longest hatred.”

At the White House, Greenblatt serves as director of the Office of Social Innovation and Civic Participation in the Domestic Policy Council, where his portfolio includes national service, civic engagement, impact investing and social enterprise.

A veteran of the Clinton administration, Greenblatt has been a serial social entrepreneur. Ethos, the bottled water company he and a business school classmate launched in 2003, donated a portion of its profits to finance water programs in developing countries. After Starbucks bought the company, Greenblatt continued to promote clean-water funding in the developing world as the coffee company’s vice president of global consumer products. He went on to serve on the board of the nonprofitWater.org, which was co-founded by the actor Matt Damon.

Greenblatt also started an open-source platform for volunteers called All for Good, served as CEO of the media company GOOD Worldwide and founded the Impact Economy Initiative at The Aspen Institute. He has a master’s degree in business from Northwestern University’s Kellogg School of Management.

In the Jewish world, Greenblatt has served on the board of the Jewish Community Foundation of Los Angeles, and he was one of the judges in the 2011 “Next Big Jewish Idea” contest of the Los Angeles Jewish federation.

“I have enjoyed a varied career that has spanned business, nonprofit and public service, but the common thread linking these experiences has been a commitment to tikkun olam, to repair the world, whether by building businesses, creating products, driving policy or forging partnerships,” Greenblatt said in his speech Thursday.

As ADL succession committee members winnowed down their top candidate choices from 25 to 15 to eight and then to three, Barry Curtiss-Lusher, the chairman of the committee and ADL’s national chairman, said he realized that, while “a number of people could be great leaders of the ADL, Jonathan Greenblatt was the best choice.”

Curtiss-Lusher also told JTA that while Greenblatt has not been a Jewish communal professional, he is a committed Jew who maintains a kosher household and is an active member of his Conservative shul.

Foxman will formally hand over the reins to Greenblatt on July 20.

Foxman has been a singular leader for the organization. A child survivor of the Holocaust, he started at the ADL in 1965. Under his leadership, ADL expanded its reach with 30 regional offices across the United States and an office in Israel. In 2011, the last year for which data is available, the ADL reported nearly $54 million in revenue.

But Foxman’s role transcends that of leader of an organization that monitors anti-Semitic activity, offers discrimination-sensitivity training and runs anti-bigotry programs, including for law enforcement. He has become the leading global arbiter for what constitutes anti-Semitism, the go-to person for apologies and exculpation when public figures make anti-Semitic gaffes or missteps, and a favorite hated figure of anti-Semites worldwide. He also has been a staunch advocate for Israel.

“I’m confident that ADL will continue to thrive and grow under Jonathan’s leadership,” Foxman said in a statement. “I look forward to working with him to ensure a successful and smooth transition.”

Greenblatt said he is deeply honored to have been chosen for the post.

“The threats that face our community today – including the expanding specter of global anti-Semitism, the continued legitimization of anti-Zionism, and the spreading infection of cyber-hate, are serious and sinister,” Greenblatt said Thursday. “Fighting this scourge and advocating for the rights of all is not just an intellectual pursuit – it’s personal for me, a deeply held value, one that has been seared into my soul.”