When the curtain came up for a recent rehearsal of the Washington National Opera’s upcoming rendition of “Porgy and Bess,” Richard Pecantte was ready. As the soaring cadences of the iconic song “Summertime” reverberated off the walls of the Kennedy Center auditorium, Pecantte leaned in close to a craps game, then stalked off after his character lost. As the rehearsal progressed, Pecantte continued to play various roles that required him, among other things, to help carry a body offstage and change costumes twice.

Convincing as he was, Pecantte is not a professional actor. During the day, he walks the corridors of Capitol Hill, monitoring financial services as a legislative assistant for Rep. William Lacy Clay (D-Mo.). By night he is a supernumerary — a nonsinging extra — for the Washington National Opera, an accidentally discovered experiment that has become a regular pastime.

Just as Members of Congress rely on their staffs to ensure that the machinery of government runs efficiently, operas often rely on supernumeraries to create robust, realistic scenes. Supernumeraries — or supers, in the opera vernacular — do not hold speaking parts or enjoy the prestige of the principal actors, and their negligible pay renders the work effectively voluntary. But they are indispensable nonetheless.

“In my opinion, I’m casting actors,” said Jennifer Crier Johnston, who oversaw the Washington National Opera’s supers for nearly a decade. “I’m not casting breathing scenery.”

Even offstage, Pecantte, 44, has a dramatic flair. During an interview in Clay’s Rayburn office, Pecantte — dressed in work clothes rather than the faded button-up and gray railroad cap he sported during rehearsal — gestured expressively as he spoke, pausing to search for the proper words and when he found them plucking them from the air, his face brightening.

Pecantte had been working in D.C. for years when he enrolled in a Department of Agriculture graduate school Spanish class to bolster his work at the El Salvador embassy. There was an acting class in the adjacent room, and Pecantte, his interest piqued despite having no background in acting, decided to check it out.

He has since become a regular in the Washington National Opera’s supernumerary community: “Porgy and Bess” is his sixth production. He has gained an appreciation for opera, describing a “newfound total respect for the art,” and has had a chance to interact with operatic luminaries such as Plácido Domingo. In addition to the rush of appearing on stage, he said the community has kept him coming back.

“It’s for the thrill, the enjoyment, the camaraderie,” Pecantte said. “You meet all kinds of people who do it, from engineers to doctors to lawyers. People from all walks of life try out, and that’s part of the thrill.”

The men assembled in the supernumerary dressing room before the rehearsal bore out Pecantte’s description. Robert Smith, a 45-year-old who works in security for the Transportation Security Administration, said this was his first return to theater since college, joking, “I figured that it’s easier to do this, try to run two marathons and jump out of a plane than find a wife.” Past supers have included actors trying to break in, Hill staffers and employees of institutions such as the World Bank.

The role of supers varies from opera to opera. Some operas do not employ any supers at all; in others, the supers can vastly outnumber the principals. In “Porgy and Bess” there are about half as many supers as principals. Dominique Croke, who manages the opera’s supers, said that “Porgy and Bess” requires the supers to be particularly dynamic.

“They’re not just standing there,” Croke said. “They have lots to do and lots to react to on stage, so they’re very important to the show.”

This was evident for anyone observing Pecantte. After he lost the craps game, he reappeared on a suspended bridge above stage, conversing animatedly with women folding laundry and gesturing eagerly to the activity below. When a character referred to Bess as a “liquor-guzzlin’ slut,” he jumped in unison with the rest of the cast. His actions fit seamlessly with what was unfolding around him, but unless one was to make a point of watching him, he blended in. This, according to Johnston, is how it should be.

“Sometimes the audience doesn’t know what’s missing in the production or what’s not right, but if some super is not in character it takes away from the lead characters,” Johnston said. “That’s what makes a show good — I have seen people who can hardly walk onstage and they stand out like a sore thumb, and I think there’s nothing worse than a super pulling focus.”

In acting as in politics, Pecantte said, timing is essential — just as a supernumerary missing his cue can mar a production, a politician’s reputation can suffer from a poorly timed run for office or an ill-advised statement spoken in improper context. But the greatest similarity between the two halves of his day, he said, is that they are both in service to the public.

“You’re trying to do your best — in the case of a politician you’re trying to help a constituent, it could be as small as a casework,” he said. “And for the audience as an actor, you’re trying to get a response, to convey something in a positive way, to make them feel what you feel. The best caseworker is someone who can understand a constituent and to some extent empathize with that constituent. It’s that same joy and fulfillment as when you get an applause — that you affected their life at some point in time.”

Pecantte said his boss has been accommodating about allowing him to balance his work with his hobby, noting that he’s never been more than 10 minutes late to rehearsal. While it’s unclear whether Clay will get a chance to take in “Porgy and Bess,” Pecantte said that Clay has expressed an interest in taking his parents to a show.

“They’re going to try and make a matinee,” Pecantte said, laughing.