In some ways, the Anti-Defamation League’s new director, Jonathan Greenblatt, could not be more different from its recently retired longtime head, Abraham Foxman of Bergen County.

To begin with, there are the visuals. Mr. Foxman is so warm that it’s practically visible; of course the warmth masks steel, but you can’t see it. Mr. Greenblatt is all hard edges; light bounces off his head. There is real heat, but the steel is on the outside. Mr. Foxman is courtly; Mr. Greenblatt is tightly wired and all business. Those differences mark not only the very real dissimilarities between their personal styles and their histories — Mr. Foxman, 75,  was born in Poland at the start of the Holocaust and brought up as a Catholic to save his life; Mr. Greenblatt, 45, was born in the United States, the grandson of a Holocaust survivor — but of the very different times in which they grew up.

Although their approaches reflect their generations, though, their passion is shared — “stopping the defamation of the Jewish people and securing justice for all,” as Mr. Greenblatt puts it.

That’s been on display most recently in the ADL’s quick response to Republican presidential hopeful Donald Trump, whose denunciations of entire ethnic or religious groups, and later refusal to condemn David Duke and the Ku Klux Klan, immediately was met by the ADL’s offer to educate him on homegrown hate groups.

Mr. Foxman, whose tenure at the ADL took him through a full 50 years of change, retired (or at least sort of retired — he is far too fully engaged in the world to retire completely) in July, and Mr. Greenblatt became the ADL’s sixth national director.

One of his early moves there was to hire Shari Gersten of Tenafly, who became the ADL’s first vice president of leadership and external relations. Recently, the two of them talked about themselves, their paths to the ADL, and their vision for it.

Jonathan Greenblatt

Jonathan Greenblatt

Mr. Greenblatt wastes little time on getting-to-know-you small talk. His qualifications for his job are impressive. In 1992, as a brand-new college graduate, fresh from Tufts, he worked for candidate Bill Clinton’s presidential campaign, and later was a special assistant to President Barack Obama and director of the brand-new Office of Social Innovation and Civic Participation. He is an entrepreneur, and much of his success has been at the intersection of business and social-justice work. As one of the founders of Ethos Water, he sold expensive bottled water and channeled some of its profits into providing free water to children in developing countries.

He is also very much of his time; much of Mr. Greenblatt’s work has involved cutting-edge technology, particularly around social media. All For Good was an open source platform and Good Worldwide was a media company; they both were profit-making ventures, and the fact that both had the word “good” in their names was not accidental. Mr. Greenblatt is a firm and genuine believer in doing well by doing good.

Mr. Greenblatt also has been very clear about his deep connection to the Jewish world.

Given that background, he was a logical choice to head the ADL — Mr. Jewish Twenty-first Century, replacing the quintessential Mr. Jewish Twentieth Century, Abe Foxman.

As he started talking in his midtown office recently, Mr. Greenblatt talked in bullet points about his four goals for the ADL as he “takes it to the next level and leads it into the future.”

First, he said, is renewing its mission to protect Jews and fight for social justice for all. “That’s why Benjamin Epstein” — the ADL’s director before Mr. Foxman — “marched with Martin Luther King at Selma,” he said. “It’s why in the 1950s we were fighting for immigrants and refugees, why in the 1940s we were advocating for the Jewish state, why in the 1990s we were pushing for laws against hate crimes. For generations we have been fighting for civil rights and social justice for African Americans and Latinos, along with fighting for Jews. For decades we have been fighting for both.

“In recent years, some of the emphasis has shifted, and there has been some lack of clarity. So how do we build on our heritage as we embrace our Jewish values? How do we embody the fight for social justice?” One of the ways, he suggested, is to work to get legislation against hate crimes passed in all 50 states, to ensure that the laws cover sexual orientation and gender identity, and “to make sure that law enforcement effectively tracks hate crimes, because many crimes are not reported,” he said.

His second goal is to “reinvigorate the operation.” To that end, his “first senior hire was a new head of HR. And it wasn’t someone who came from a JCC or a federation. It was a 15-year veteran of GE who had worked at Citigroup, and who is an expert in bringing the best practices of Fortune 500 companies to our organization.” (He was talking about Thomas Ruderman, who is now the ADL’s senior VP of talent and knowledge.)

“How do we upgrade our capability in order to be as effective and high performing as possible, from launching a Twitter feed in Arabic to integrating internal models so we can better commit to identifying talent?” he asked rhetorically. “We will grow by learning from the private sector.”

The third goal, Mr. Greenblatt said, “is to engage broadly with the younger demographic.” The generation below his, the millennials, is “more intermarried, less affiliated, less institutional, more about inventing solutions to problems. They want to change the world themselves, so we have to think deeply about how to engage with them.” He is talking not only about secular millennials but about religiously engaged millennials as well.

And why should millennials not be religious? “Orthodox millennials are a quickly growing community, and we need to be mindful of them”; we should not think in binary terms, he warned. “We have 5,000 years of values, and we should use it to connect with all sides of the community.

“Within the Jewish community, we need to reach out to a younger crowd, across the spectrum of observance and practice. We must reach out to the non-Jewish community. I am proud that we advocate for Syrian refugees. Most of them are women and children, widows and orphans and the elderly. It is the right thing to do — we were once strangers ourselves.”

He is not advocating naiveté, he continued. “I was in Europe a few months ago, and I saw how Belgian and French Jews live.” They are afraid, and with good reason. The ADL has an obligation to help them. “I do not think that helping European Jews and Syrian refugees is mutually exclusive. Instead, it is reinforcing.”

Jonathan Greenblatt stands at a memorial to the victims of the terrorist attack at the Hypercacher supermarket in Paris.

The fourth goal, Mr. Greenblatt said, “is to make big bets. I don’t want to boil the ocean — but how do we convert challenge to opportunities?”

Much of the ADL’s job is balancing competing realities. Take the still-highly-controversial Iran deal, struck just as Mr. Greenblatt took on his new job. “We didn’t support it, but we had to focus on the day after.” The fissures that it exposed need tending; they must not be papered over but have to be repaired. “We need to be tolerant. We have to model the kinds of behaviors we expect to see, a respect for different points of view. We have to have conversations, even when they are tough. Our whole tradition is about dissent.

“One big bet is how we strive for more civility and constructive conversation in our own country.

“And we know that anti-Semitism is not going away. The first phase of anti-Semitism was anti-Judaism, coming from the early church. The second was a racial thing. And now we have anti-Zionism, which is anti-Semitism. We have campaigns like BDS, which is unambiguously anti-Semitism. It has become very sophisticated, but it is anti-Semitism, and we need to be prepared to confront it.

“We will be robustly engaged in the fight against anti-Semitism and in the fight for social justice,” he concluded. “That is where I see us going. Whether it is the new civil rights struggle of the day, fighting the deligitimitzation of Israel, pushing back against those who oppress us or others, getting young people engaged — that is the struggle of our time.

“And I am blessed to be in an organization with such a rich history.”

Mr. Greenblatt grew up in Trumbull, Connecticut, in a town that was not particularly rich in Jews but to a family that was deeply connected to Jewish life. Three of his four grandparents were born in Europe, and “my grandfather had us marching for the refuseniks at the JCC when I was a kid, and the funny thing is that it worked. They were freed. So early on, I got this Herzl-ian idea that if you will it, it will be. It happened. These early experiences gave me the sense that anything could happen.

When he worked for the Clinton campaign, Mr. Greenblatt said, he met Lenny Zakim. The Boston-based Mr. Zakim, who grew up in Clifton and died in 1999, when he was 46, was a remarkably influential and beloved Jewish communal activist. Mr. Zakim was a huge influence on his life.

Mr. Greenblatt and his wife, Marjan Keypour, an Iranian Jew and human rights activist who came to this country when she was 17, have three children. “My wife is far more interesting than I am,” Mr. Greenblatt said.

“We are not all either Ashkenzai or Sephardi,” he added; the idea that all Jewish food is one or the other — that binary idea — is so wrong! But as a community we do struggle with “duality. How do you manage it? How do you live with it?” We are Americans and we are Jews.

He is grateful to be able to talk with Mr. Foxman. “I am blessed to be in an organization with such a rich history. I talk to Abe frequently. I am lucky to have his ears and his counsel.”

Mr. Foxman agrees. “Jonathan is smart,” he said. “Very smart. He comes to the ADL with a very different set of skills than I had, and they are very important in today’s age. He will apply them and move the agency further in this new era. He has the passion, he has the understanding, he understands our mission, and he is dedicated to it.

“It will be different, but in a certain way it will also be the same. The voice will change, the photos will change — he has his own understanding, his own history and emotions — but the mission won’t change. He will carry it forward.

“I am very optimistic about the ADL’s future under Jonathan’s leadership.”

Ms. Gersten, a lawyer, “worked for three years doing labor litigation, and I hated it,” she said. “I worked on the Clinton campaign, and I worked with Ron Brown. When he became commerce secretary” — Mr. Brown was a chair of the Democratic National Committee, and Mr. Clinton appointed him secretary in 1993; in 1996, while on a trade mission, he was killed in a plane crash in Croatia — “he asked me to join him, and I decided that I wanted to do something substantive.”

In 1997, Ms. Gersten and her husband, David Rosenblatt, moved to Boston, and then to Silicon Valley, where she worked in a small start-up, and where their twins, Arielle and Zeke, were born. “When they turned 2, we decided that Jewishly there wasn’t enough for us there,” she said. “We used to have to get our kosher meat from 45 minutes away. We felt that if we didn’t have a strong Jewish community, it would be like raising our kids on an island.”

Ms. Gersten is from Scarsdale, N.Y., so it was natural to move back to the metropolitan area, “and we had friends in Englewood. We knew that we wanted a Jewish day school, and to be as close to Manhattan as possible.” They moved to Tenafly, where the twins began prekindergarten at the Solomon Schechter School of Bergen County. (The school goes through eighth grade; they graduated and now are in high school at the Solomon Schechter School of Westchester.) The family became active in local Jewish life; Mr. Rosenblatt is a former Berrie Fellow at the Jewish Federation of Northern New Jersey and now sits on the executive board of the Kaplen JCC on the Palisades in Tenafly. (As we chronicled in 2011, Mr. Rosenblatt also is one of the founders of the Arava Power Company, an Israeli solar energy concern.)

Shari Gersten with her husband, David Rosenblatt, and their children, Arielle and Zeke.

Shari Gersten with her husband, David Rosenblatt, and their children, Arielle and Zeke.

Because their daughter Shari lives in Tenafly and their other daughter is on the Upper West Side, recently Ms. Gersten’s parents, Roz and Gerald Gersten, who spend part of the year in Florida and used to spent the other in Westchester, moved to Fort Lee to be closer to them. “My father flew 33 bombing missions over Germany in World War II,” his daughter said. “He is my hero.”

Like Mr. Greenblatt’s grandparents, Ms. Gersten’s were European-born. “When I turned 50 last year, my husband asked me what I wanted to do, and I said that I wanted to go to Moldava, where my grandfather came from. My grandfather left in 1922. He and two brothers walked to Palestine. He got sick with malaria, and he was told that if he didn’t leave he would die. He had a friend from Poland who sent him passage to New York, and his first day there he met my grandmother, who was from Russia, in Prospect Park.

“His two brothers remained in Palestine, and the rest of his family was killed in Sobibor.”

Last year Ms. Gersten made the pilgrimage to Sobibor; she also went to Poland and saw Auschwitz. “My grandfather and I were very close, and now that I have been to his town I understand more about his story, and about how lucky he was,” she said.

Shari Gersten, of Tenafly, shown here in Poland, is the AOL’s new first vice president of leadership and external relations.

Shari Gersten, of Tenafly, shown here in Poland, is the AOL’s new first vice president of leadership and external relations.

To get back to duality — what Ms. Gersten saw in Poland embodied that. She saw the death camps; she also saw life. Poland’s government is now newly and worryingly right-wing; at the same time, “more and more Polish people are finding out that they had relatives who were Jewish, and they are deciding that they want to learn more, to be more Jewish. My joke with David is that my one-time bucket wish was to go to Poland, and now I have been there twice within the last six months, and I am hoping to go again this summer.”

She recently agreed to join the board of the JCC in Krakow.

When her friend Jonathan Greenblatt asked Ms. Gersten to join him at the ADL, “I felt really blessed, as a Jew, as a person,” Ms. Gersten said. “It is such an honor.”

Ms. Gersten works with the ADL’s lay leaders and nurtures the next generation, who gradually will step up to leadership roles. “The future is with the young leaders,” she said.

“I feel blessed every time I walk in and see our mission statement on the wall. I look at it every day, because it energizes me.”

She also is thrilled to work with Mr. Greenblatt. “Jonathan is incredibly special,” she said. “He has such a neshama” — such a soul. “He cares so much for the Jewish people.”