‘Maestro’ revels in multifaceted Bernstein

There is a stunning moment in “Maestro” as Hershey Felder, playing Leonard Bernstein’s alter ego on stage, and the conductor-composer himself, on a large screen in an old film clip, join in a seamless piano duet from Richard Wagner’s “Tristan and Isolde.”

This tour de force at the Geffen Playhouse characterizes the fusion between the personas of actor-singer-writer Felder, very much alive and lively at 42, and Bernstein, who died almost 20 years ago at 72.

There are, to be sure, some resemblances between the two men. Both sons of Eastern European immigrants grew up in Yiddish-speaking homes and in tightly knit Jewish communities, Bernstein in the Boston area and Felder in Montreal.

The similar backgrounds pervade “Maestro: The Art of Leonard Bernstein,” sprinkled with Yiddish and Hebrew expressions and with a considerably stronger Jewish content than Felder’s earlier concert-play — an art form of his own invention — “George Gershwin Alone.” (Bernstein referred to the “Rhapsody in Blue” composer as Yankele (Jacob) Gershowitz, Gershwin’s birth name.)

“Maestro” works on several different levels. One is as a biographical tour of Bernstein, the musician, from precocious youngster to Harvard graduate (under the 10 percent “Jewish quota”) to assistant conductor of the New York Philharmonic.

There is the historical date of Nov. 14, 1943, when, in a pure Hollywood fantasy, a hung-over Bernstein is awakened by a phone call telling him that conductor Bruno Walter has suddenly fallen ill and that he, the 25-year-old Lenny, must substitute at 3 p.m. that day.

Bernstein, of course, triumphs — and the rest is history.

“Maestro” introduces us to the great conductors who influenced Bernstein, each infused by Felder with a distinct personality and European-Russian accent. We meet the likes of Walter Damrosch, Dimitri Mitropoulos, Fritz Reiner (“with the permanent expression of a man who had sex once and didn’t like it”), Walter, and, above all, the beloved Serge Koussevitzky.

On a second level, there is Bernstein the composer, whose works like “Jeremiah,” “Dybbuk Suites” and “Kaddish” reflect his deep Jewish roots.

As a world-famous conductor, Bernstein also turns to the musical stage, from “On the Town” to “Candide” and the triumphant “West Side Story,” the latter a modern version of “Romeo and Juliet.” (Originally Bernstein had cast the two warring families as Jews vs. Catholics, but cooler heads prevailed, he said, “So we threw out the Jews and brought in the Puerto Ricans.”)

On the third level, there is Bernstein as the complex and conflicted human being. He was happily married to his beloved Felicia, the mother of his three children, but took little pains to hide his various liaisons with men.

“Maestro” opens with Bernstein on his deathbed, and Felder believes that for all the worldly acclaim, Bernstein pronounced a harsh judgment on himself.

Bernstein’s greatest sorrow was that he never composed the one superb masterwork that would immortalize his name, Felder said during an interview at the Geffen, looking half the age of his bewigged stage persona.

In his later years, “Bernstein also suffered from a strong feeling of guilt,” Felder said. “He shoved [his affairs with men] down Felicia’s throat, and he didn’t care how devastated she was.”

“Maestro” runs close to two hours, without an intermission, and the sheer physical stamina required for the one-man play is astonishing. The more so as Felder throws himself into the role with unreserved physical and emotional passion, which stops just short of going over the top.

The one exception is an odd song, “I Hate Music,” which Felder accompanies with outrageous mugging.

But perhaps Felder’s greatest pedagogic service to his audience is to transmit a real feeling for the creative processes underlying the art of conducting and the art of composition.

For his own musical works, Felder connects with his heritage with such compositions as “Aliyah, Concerto for Piano and Orchestra,” the opera “Noah’s Ark” and his recording of “Love Songs of the Yiddish Theatre.”

Besides his concert-plays on Gershwin and Bernstein, he has also brought Beethoven and Chopin to the stage. For a change of pace, however, he is now working on a new musical, “Nine Hours on Tenth: The Unknown Story of President Lincoln’s Last Day.”

When not touring, Felder lives in Paris with his wife, Kim Campbell, a former Canadian prime minister, whom he met while she was serving as her country’s consul general in Los Angeles.

“Maestro,” directed by Joel Zwick, continues at the Geffen Playhouse in Westwood through Dec. 12.