That is the evolving community that Rosenbloom is leaving to a soon-to-be-named successor at the 650-family synagogue. Rosenbloom, who announced his plans to retire in November 2012, will step down June 30.
His retirement marks a shift as rabbis whose views were shaped during the unrest of the 1960s, the Israeli victory in the Six-Day War, and the growth in consciousness about the Holocaust move on, said Arnold Eisen, chancellor of the Jewish Theological Seminary in New York.
Rabbi Elliot M. Strom of Shir Ami in Newtown, Bucks County, is also retiring in June, after 35 years at the synagogue.
Rosenbloom is among the longest-serving synagogue rabbis in the area. He joined the then 1,000-family congregation in 1978, just six years after graduating from the Jewish Theological Seminary.
"I was in over my head when I came here," said Rosenbloom, who was then 33. "It took me five or six years to know what I was doing, and I've been learning ever since."
During his tenure, he has officiated at hundreds of bar and bat mitzvah ceremonies, baby namings, confirmations, brises, and funerals.
On Saturday, about 400 of those for whom the ceremonies were held came back to honor the rabbi at a Reunion Shabbat.
Shotz, who traveled from Los Angeles, told them about a crucial 1996 meeting he had with the rabbi.
"I told him of my struggles in coming to terms with being gay," said Shotz, who grew up in Melrose Park.
The rabbi gave Shotz a notebook stuffed with essays by people who are gay and Jewish. Rosenbloom had assembled the collection for Shotz at a time when gay rights was an unpopular cause.
"He encouraged me to be completely open, and that I could find my way through all of this to make who I am, and what Judaism is, work for me," said Shotz, 40, the owner of a film-production company who went on to found a bar and bat mitzvah training program.
Rosenbloom has built a reputation for delivering evocative sermons, taking controversial stands and nudging his congregants to evolve with him as he has changed with the decades.
"He understands that being Jewish is different for everybody," said Check, 36, of Maple Glen, who grew up at Adath Jeshurun and who describes herself as nonreligious. "If Shabbat dinner is sitting down and having pizza, then that is OK."
Rosenbloom, who was born in Rochester, N.Y., has come to embrace marriage between Jews and people of other faiths, and spoke out about LGBT rights in a High Holy Days sermon in 1994.
He called the Iraq War a mistake, is in favor of the establishment of "a Palestinian state within the context of a peace agreement with Israel," and said "some of Israel's actions have been impediments to peace."
Some have left the congregation because they disagreed with his positions, Rosenbloom said.
"He asks his congregants to open their minds to think about things in different ways," said Rabbi Fredi Cooper, assistant professor of practical rabbinics at the Reconstructionist Rabbinical College in Wyncote and a former associate rabbi at Adath Jeshurun.
Cooper credits Rosenbloom with being the first - along with Cooper's daughter - to suggest that she consider becoming a rabbi.
"He saw something in me," Cooper said.
Rosenbloom is retiring at a time when affiliation rates are down, intermarriage is up, and the Old York Road corridor of synagogues where Adath Jershurun sits has lost its popularity as a place for young Jewish families to settle.
His successor will have to build a community during a time when people prefer their religion a la carte, Rosenbloom said. They may want Hebrew school and High Holy Days services, but not synagogue membership.
A younger rabbi will be more adept at the innovation necessary to cope with change, he said. Rosenbloom, who is married and has a blended family that includes five children, plans to stay on as "distinguished service rabbi" and help his successor in whatever way the new rabbi chooses.
"When I came to the synagogue it was clear what a synagogue was and what a rabbi's job was," Rosenbloom said, "I was to serve the congregation; today's rabbis" will have to create one.