NEW YORK (AP) — When David Leigh sang “The Impossible Dream” at his father’s funeral, the moment was both a testament to his past and a harbinger of his future.

Leigh, an operatic bass, is the son of Mitch Leigh, who wrote the score for the musical “Man of La Mancha,” one of Broadway’s biggest hits in the 1960s — long before David was born.

When Mitch died in 2014 at age 86, David was studying voice in the graduate program at Yale and still finding his way as a singer.

“My dad was very anxious for my career to get going so that he could still be alive to hear me have some success,” Leigh said.

Sadly, that didn’t happen. But now, at 36, Leigh is finding his dream of an operatic career is not so impossible. In fact, he’s fast establishing himself as a future star in the lowest-lying roles for male voices.

This month he’ll take on a major role as the jailer Rocco in a new production of Beethoven’s only opera, “Fidelio,” at the Washington National Opera, which opens Friday.

“He’s going to be the real deal,” said Francesca Zambello, WNO's artistic director, who cast him in the part. “A bass that young with that powerful a stentorian quality is rare.”

Andreas Homoki, the outgoing Zurich Opera artistic director, recalled that last year he had been looking for “somebody special, not one of the established artists” to sing the role of the villainous Hagen in the final opera in Wagner’s “’Ring” cycle.

He cast Leigh — and was delighted with the results.

“Apart from his incredibly powerful voice and his noticeable physical stature, (Leigh stands 6-foot-5) he is able to transmit a very special vulnerability,” Homoki said. "Having in mind how relatively young he is compared to his colleagues in the same repertoire, it is hard to imagine him not having a brilliant career all over the world.”

Gianandrea Noseda, music director of the Zurich Opera who conducted the “Ring,” was impressed with the “‘nobility, an aristocracy of singing” that Leigh brought to his role.

In many professions, 36 would not seem young, but some operatic voices, including basses, can take years to settle in. “It’s a longer fermentation process,” Zambello said.

For several years earlier in his career, Leigh said his relative youth actually counted against him. Many of the iconic roles for basses are characters who are no longer young men.

“When I was auditioning all the time, people would say ‘May I ask how old you are’? And when I told them, they’d say, ‘Oh, you’ll get to sing this when you’re older.’

“Once a few gray hairs started coming in on my beard, I was very excited,” Leigh joked.

The tradeoff is that many basses go on singing well into their 60s or even later. Leigh cited the example of the great Soviet bass Mark Reizen, who famously performed Prince Gremin’s aria from Tchaikovsky’s “Eugene Onegin” at age 90.

Leigh said he always had an unusually low singing voice, but when he first enrolled at the Mannes College of Music in New York after Yale, he said, “I didn’t really know what I was doing.”

Joshua Greene, one of his coaches there, recalls that Leigh came to Mannes “with a totally unfinished voice, large but unrefined.

“The low notes were of a quality you don’t hear often, even on high-level professional stages,” Greene said, “but otherwise it wasn’t clear what was there. It has been very exciting to see David develop over the many years we have worked together.”

Now Leigh comfortably commands a range of nearly three octaves, from G above middle C down to A below low C.

Among the roles he most hopes to sing in the near future, Gurnemanz from Wagner’s “Parsifal” tops the list. In fact, he was scheduled to perform it with the Canadian Opera Company in the pandemic-canceled season of 2020-21.

“It’s the most beautiful music ever,” he said. “It’s in a range where I can be perfectly expressive. I can sing every phrase and say exactly what I want to say.”

Also high on his list are King Philip from Verdi’s “Don Carlo” and some of the great Russian roles, like the title character in Mussorgsky’s “Boris Godunov.”

And what of “The Impossible Dream,” the biggest hit song from “Man of La Mancha.”

While his father was living, Leigh was “very resistant” to singing it. “It kind of felt like nepotism,” he said.

That changed at the funeral, and now he happily performs it as an encore after recitals.

“It was a crazy moment,” Leigh said. “It suddenly felt beautiful for me to sing it.”