David Unterman’s 86-year life was a series of serendipitous and sometimes catastrophic events that took him from an Orthodox community in Brooklyn to the Lamplighters in San Francisco, where he became the group’s first bass baritone lead, and back to Broadway and the Metropolitan Opera. But suddenly in 1961, complications from polio, which he suffered at 20 months, shattered his ankle and terminated his show business career.

Cantor emeritus David Unterman

But his most rewarding career, he said, was as a cantor. Beyond the pulpit at Reform Congregation Beth Am in Los Altos Hills, where he served from 1981 to 1997, the beloved cantor emeritus was perhaps best revered as a teacher who inspired students, from the b’nai mitzvah youth he coached to the octogenarian faithful in his Jewish spirituality class.

“I came to see that although he was blessed with a rich cantorial voice, his true love and his true passion was teaching,” said Janet Marder, senior rabbi at Beth Am. “He loved to study and explore questions of theology.”

Don Allen, a decades-long friend and student, agreed. “He was a masterful teacher. … He didn’t want to just stand up and lecture. He tested as he went, asking his students what they thought, hoping to evoke ‘aha’ [moments]. … That was [his] hallmark.”

Unterman passed away March 26 in his San Jose home from multiple illnesses, complicated by the aftereffects of polio. His wife, Carol Carter, who became his caregiver, said her husband continued teaching until just weeks before he died, propelled by his passion for learning and for Judaism.

Though Unterman had been singing his entire life and had performed in Orthodox synagogues as a child, he hadn’t considered the cantorate until after his 1961 accident. He had been hospitalized for over a year and was at a loss regarding his next career move when the hospital social worker and therapist suggested the cantorate.

Applying to the Reform movement’s Hebrew Union College, he told the interviewers he was an atheist, but “that didn’t bother them,” he said in a 2009 videotaped interview with former Beth Am cantor Lauren Bandman. After five years of study, he was ordained in 1967 and served in several pulpits, including Temple Sinai in Oakland, before joining Beth Am.

Did he remain an atheist? Carter wasn’t sure. “He felt there was some force in creation,” she said. “When someone said he didn’t believe in God, he would say, ‘What God do you not believe in?’ ”

Carol Emerich, who grew up at Beth Am and filled in as facilitator for his Thursday afternoon spirituality class when he became ill, described Unterman as “a Jewish agnostic, always questioning. … Even though intellectually he didn’t believe in God, when he needed somebody to yell at or praise, he turned to God.”

Meanwhile, this reporter remembers his charming irreverence. Teaching a workshop during an Asilomar retreat several years ago, he sang a few bars of Gershwin’s “It Ain’t Necessarily So,” and then in the same tune, with an impish grin, segued to the liturgy, “Bar’chu et Adonai ham’vorach.”

Atheist or agnostic, his soulful singing drew congregants to Beth Am, including Emerich’s father, a founding member who began attending services again. Not to mention Carter, who has described him as the missing link between the old chazzanut (the emotive style of Eastern European-trained cantors) and the modern folk-inspired cantors. In 1981, she joined Beth Am just as Unterman began working there. “I was sitting in the congregation and when he started to sing, the service went from black and white to color. I was hooked,” Carter said. They married in 1991.

“Dave had an incredible vocal instrument, but he was a teacher at heart. I will miss his philosophical outlook on life, and that twinkle in his eye,” said cantor emerita Kay Greenwald, now director of placement for the American Conference of Cantors. She described him as a “dear friend and something of a mentor to me. … He taught me to remind b’nai mitzvah and their families of the wonder of being surrounded by supportive community and the people who love you most.”

She added: “Moreover, it was Dave who gave me the language to use with young people who were nervous about standing up in front of their congregations: He used to say, … ‘You are only nervous because you care — and isn’t it better to care?’ I have used this language ever since.

In the video interview, Unterman described the transformation in services after he came to Beth Am, adding “spirituality to a highly intellectual atmosphere.” When he auditioned, he said, “they accepted me because of my singing, and I got the congregation singing. They used to sit on their hands.”

A memorial service will be held at 4 p.m. April 17 at Congregation Beth Am, 26790 Arastradero Road, Los Altos Hills.