Mr. Eckstein exits a plane arriving at Ben Gurion airport near Tel Aviv in 2002. (Pier Paolo Cito/AP)

“No Jew since Jesus has commanded this kind of gentile following,” journalist Zev Chafets once wrote of Yechiel Eckstein, an Israeli American rabbi who — with extravagant success, and more than modest controversy over three decades — rallied moral and financial support for Israel among American evangelicals.

Mr. Eckstein, 67, who died Feb. 6 after a heart attack at his home in Jerusalem, founded the International Fellowship of Christians and Jews in 1983. Established in Chicago, the organization is today building a new headquarters in Jerusalem. The group reports that, since its creation, it has raised more than $1.6 billion to support impoverished Israelis, Holocaust survivors and Jews across the diaspora; to bring Jews to Israel; and to serve ethnic minorities including Arabs in the Jewish state.

Much of that money came in small donations from evangelicals in the United States, a population that few Jewish leaders before Mr. Eckstein had attempted to reach. He sought to overcome the distrust that had long colored the relationship between the two faiths, harking back to a passage in Genesis: “I will bless those who bless Israel and curse those who curse Israel.”

He appeared in commercials or infomercials that aired on outlets including the Fox News Channel and Pat Robertson’s Christian Broadcasting Network, campaigns that met with enormous success.

“I have people sending me 10 percent of their Social Security checks,” he once told the Jerusalem Report, “car washers in Florida writing to me to help the elderly Jews in Kiev buy fuel; a 53-year-old man so touched by my newsletter that he sent me his entire life savings — $ 11,000 — which we returned.”

As his profile grew, Mr. Eckstein became a force on both sides of the theological divide. In Israel, the Fellowship became one of the country’s largest charitable organizations. Israeli President Reuven Rivlin lauded Mr. Eckstein as “a great man, a great Jew and a great Zionist.”

In the United States, Mr. Eckstein formed close relationships with evangelical leaders including Robertson, Jerry Falwell and Ralph Reed. He met with leaders including Condoleezza Rice, then serving as President George W. Bush’s national security adviser, and in 2018 held a Fellowship gala at President Trump’s Mar-a-Lago Club in Florida.

But along with influence came criticism. Some Jews opposed his association with the religious right, whom they viewed as proselytizers motivated by a biblical prophecy linking the return of Jews to Israel with the Second Coming of Christ.

“Eckstein is selling the dignity of the Jewish people and the state of Israel by pandering to Christians for money,” Abraham Foxman, the longtime national director of the Anti-Defamation League, once told the Jerusalem Report.

Further complicating the interfaith relationship were political differences, with many American Jews traditionally leaning left and evangelical Christians leaning right. Mr. Eckstein conceded that when, as an Orthodox rabbi, he first brought Falwell into a synagogue, he was met with astonishment. In an interview with CBS News, he recalled the reaction: “Has Yechiel Eckstein gone off the deep end or what?”

To his supporters, his success spoke for itself. Among Mr. Eckstein’s largest-scale initiatives was the “On Wings of Eagles” campaign to bring Jews from the former Soviet Union to Israel. Other beneficiaries of Fellowship funds included Ethio­pian Jews newly arrived in Israel; Israelis who could not afford shelter, heat, cooking appliances or other essentials; students in need of school supplies; and hospitals lacking basic medical equipment. So extensive was his work that he became known as “the Jewish state’s unofficial welfare minister.”

Yechiel Zvi Eckstein was born July 11, 1951, in Winthrop, Mass., and grew up in Ottawa, where his father was chief rabbi of Canada. His mother was a homemaker.

He received a bachelor’s degree and a master’s degree in Jewish philosophy from Yeshiva University in New York, where he also received his Orthodox rabbinical ordination in 1975, and a master’s degree in philosophy from Columbia University.

Early in his career, he worked for the ADL. In 1977, the organization sent him to Skokie, Ill., where neo-Nazis were organizing a demonstration in the community that was home to many Holocaust survivors. Mr. Eckstein found — and sought to cultivate — support among evangelicals moved by a literal interpretation of the Bible holding that Jews were God’s chosen people.

Finding little backing for his efforts within the ADL, he left the organization and founded his fellowship. He received no income and reportedly supported his young family by working as a part-time rabbi and as a wedding singer. In 2014, according to the Wall Street Journal, he received a salary of $512,000, as well as a $544,000 contribution to his retirement fund.

Mr. Eckstein moved to Israel in 2001 and became an Israeli citizen the following year. His death was confirmed by George Mamo, the global chief operating officer at the Fellowship.

Mr. Eckstein was the author of books including “How Firm a Foundation: A Gift of Jewish Wisdom for Christians and Jews” and “What You Should Know About Jews and Judaism.” He was the subject of an authorized biography, “The Bridge Builder,” by Chafets.

Mr. Eckstein’s marriage to Bonnie Siegman ended in divorce. Survivors include his wife of 12 years, the former Joelle Medina of Jerusalem; three daughters from his first marriage, Yael Eckstein-Farkas of Pardes Chana, Israel, Talia Eckstein-Harrow of Miami and Tamar Pugliese of Teaneck, N.J.; his mother, Belle Eckstein of Jerusalem; two sisters; a brother; and eight grandchildren.

Speaking to Chafets, who profiled Mr. Eckstein in the New York Times, the rabbi described himself as a “nonevangelical defender of evangelicals.”

“Jews have such a cynical, negative view of these people,” he said. “They’re not religious fanatics, and they don’t have ulterior motives. These are good, religious people who love Israel and want to help. What’s the matter with that?’’

CORRECTION: An earlier version of this story incorrectly reported that Mr. Eckstein’s mother was a rabbi. She was a homemaker. The story has been updated.