Steven Reineke, the new principal POPS conductor of the National Symphony Orchestra.. (Amanda Voisard/THE WASHINGTON POST)

The conductor stifled his usual grin. Something didn’t seem right. After the orchestra finished rehearsing “La Gallina” with the Latin-funk band Ozomatli, he studied his score, perplexed, as if it were notated in Sanskrit.

“There are some interesting sounds at bar 107,” he said, his voice evoking the tones of a mid-century radio broadcaster. “The whole thing falls apart there.”

The musicians waited for his command.

“Well? Let’s see what we end up with.”

After the piece was played one more time, the National Symphony Orchestra’s new principal pops conductor, Steven Reineke, named in February, ended the rehearsal with a cheery, “That works for me.”

“You guys cool with that?” he asked.

All was cool.

Later that evening, the audience issued a more riotous verdict, with strangers adjoining hands and shoulders to form a massive conga line that snaked through the Kennedy Center’s packed Concert Hall. This week Reineke begins his three-year tenure at Wolf Trap, conducting “Disney in Concert: Magical Music From the Movies.”

Reineke looks like J.Crew cast him for its catalogue. Pairing jeans and a blue oxford shirt with his all-American boyish looks, he exudes a go-with-the-tempo style that sometimes moves his rehearsals into jam-session territory.

He begins rehearsals with announcements more appropriate for cruise directors than conductors: Ladies and gentlemen, we’re going to have a fun time this evening. He’s unexpectedly rosy, never glaring at his weakest player or frowning if his ear catches mistakes by a sluggish viola or rogue French horn.

“I come from a player’s mentality,” said Reineke, 40, sitting in a velvet chair in the Kennedy Center’s Golden Circle Lounge. “I remember making fun of a lot of conductors. Orchestras know within 30 seconds whether you have the wherewithal to be up there. I think of myself as a coach, not a dictator.”

Players find his style charming.

“He has more love for this music than anyone I’ve ever seen,” said Aaron Goldman, assistant principal flutist for the NSO. “He’s definitely a laid-back, easygoing guy, but the energy he brings to the stage is extraordinary. We can’t help but get caught up in that.”

Pops have long been the moneymaking arm of American orchestras, a venue for showcasing a mix of popular and light classical music. Now, with two-thirds of U.S. orchestras facing deficits, and the esteemed Philadelphia Orchestra in bankruptcy since April, that financial mission has taken on even greater significance. The challenge for Reineke in Washington, which has a thriving classical music scene, is to deliver the light classics and jazz standards to older audiences while finding and nurturing new ones.

Reineke seems more excited than daunted by the task.

The pops trumpeter

As part of Reineke’s rise to prominence, he became the music director of the New York Pops and principal pops conductor of the Long Beach and Modesto symphony orchestras, positions he still holds. Although he is the protege of Erich Kunzel, the famed “Prince of Pops,” who led the Cincinnati Pops Orchestra for more than 40 years, his musical history is an atypical one.

He didn’t claw his way up the ranks from a childhood of Suzuki training and games of musical first chairs. He happened upon music, taking up the trumpet in the fifth grade after “the sax didn’t work out,” the way a boy from Ohio might take up skateboarding or karate. His middle-school hobby stuck, and he majored in trumpet performance at Miami University of Ohio. He aspired to become a professional trumpet player.

“I fell into music,” Reineke said. “At a lot of public schools, unless you’re doing piano or violin, you learn music in band classes, and that’s just how it happened. It was offered to me, so I just took to it and excelled.”

He also developed a powerful urge to write music, teaching himself to play piano in high school to help him compose. “I had these tunes running around my head, and I just had to get them out,” he said. That compulsion led to another bachelor’s degree, in composition, the field in which he would linger until his mid-30s.

After college, he won a grant to move to Los Angeles, where he studied film scoring, working with Henry Mancini and John Williams. His career took off when he received a commission to write the score for a ballet staging of “Peter Pan.” Kunzel took notice, hiring Reineke as the principal arranger of the Cincinnati Pops, starting their 15-year collaboration and friendship. Again the composer transitioned smoothly, finding another home in conducting.

“It’s ultimately one of the things I’ll enjoy most in my lifetime: being able to be up on the podium and present concerts to audiences,” Reineke said.

Conducting, a calling he neither sought out nor expected, became more than a career for Reineke. In 2009, Kunzel was told that he had pancreatic cancer, and Reineke took over most of his concerts. “He was the greatest teacher I’ll ever have,” said Reineke, his booming voice softening as he described the emotional last weeks of Kunzel’s life. “During those four short months, we had a lot of real conversations about the future and his life and what he wants for mine. That’s when I knew this was it.”

Reineke was already on his way to becoming a sought-after pops conductor, but now he would continue his journey without Kunzel, the pioneer who put Duke Ellington and Ella Fitzgerald on stage with symphony orchestras in the 1960s.

Kunzel died Sept.1, 2009, the day that Reineke moved to New York City to begin conducting the New York Pops.

“It was a little bit like a passing of the torch. It wasn’t to be the next Erich Kunzel, but to be the first Steven Reineke.”

The future of pops

In decades past, pops programs resided within the safety net of light classics such as the waltzes of Johann Strauss Jr., works that appealed to older, loyal audiences. “There used to be a trust relationship with pops,” said Keith Lockhart, conductor of the Boston Pops. “Programs would say, ‘Boston Pops, 8 p.m.’ with no indication of content. Now audiences know what they want to hear, and they’re savvy about how they spend their entertainment dollars.”

In the past decade, the genre expanded rapidly to include “Lord of the Rings” scores, folk music and modern acts such as Ben Folds and Pink Martini. The generic pops concert became more in tune with modern marketing practices, homing in on the desires of information-age audiences. The tactic opened pops up to younger audiences, but also to more criticism and more questions about how to keep audiences hooked.

“The gist of pops concerts has changed so radically,” said Tim Page, a professor of journalism and music at the University of Southern California and former music critic at The Washington Post. “Today, pops tends to be more often like third-rate rock-and-rollers doing their stuff with a pops orchestra. At least it gives musicians jobs, but is having an orchestra play ‘I Love You Just the Way You Are’ serving the original idea of what an orchestra was invented for?”

In recession-stricken times, the purpose of pops has become clear: to find and grow an audience. In the past year, esteemed classical orchestras have added more pops concerts. The Dallas Symphony introduced an all-pops format to its summer concert series in 2010. Reineke conducted both the Philadelphia Orchestra and the Cleveland Orchestra this summer, which added pops concerts to their schedules even though both cities have separate, thriving pops orchestras.

“Major orchestras are seeing that pops is a moneymaker,” Reineke said. “Everyone generally agrees that pops doesn’t develop an audience for the classical concerts, but it’s great community outreach that brings in revenue.”

Finding a loyal pops audience has become increasingly difficult, though. With greater choices in entertainment, Lockhart said, the pops audience is growing but it’s also becoming increasingly segmented, which tends to make attendance unreliable.

“Audiences want hyper-specific concerts,” Lockhart said. “There’s been a separation of the audience into niche. I’m not sure what the societal reason behind this is, but we’re responding to the market needs of a post-Web audience. People don’t sit down to watch their favorite television show at 8 p.m. anymore.”

Sarah Hicks, the principal pops conductor of the Minnesota Orchestra, made a similar point. “There’s a lot of naval-gazing right now,” she said. “The classical genre isn’t everyone’s musical language, so working with a salsa or jazz artist touches different parts of community. But then we have to ask, ‘How do we foster these diverse audiences?’ ”

Large cities have the edge when it comes to promoting wide varieties of concerts to different audiences. And Washington, being a transient city with so many musical tastes, might be the perfect place for Reineke to experiment with a diverse pops repertoire.

“When we work with groups like Ozomatli or Pink Martini, it brings their fans, many of which have never seen an orchestra perform. They’ll come back,” Reineke said with certainty. “We have the great Kennedy Center here. As the nation’s orchestra, we have the responsibility not just to do one thing. We have to have variety, but also have to stay true to our core audience.”

Reineke is not willing to forgo jazz and musicals, the standards that endeared the pops genre to many audiences. “I never want to lose where we came from,” Reineke said. “I love the songbook. I live and die by that music, but I want it to be fresh and new.”

Reineke’s first NSO pops season embraces the standards, beginning with “The Music of Rodgers & Hammerstein,” starring Broadway’s young Kelli O’Hara and tenor Aaron Lazar. The season also includes a tribute to Nat “King” Cole, and comedian Wayne Brady will solo in “Wayne Brady Sings the Sammys,” a tribute to Sammy Davis Jr. and Sam Cooke. The Canadian Tenors and the popular swing band Big Bad Voodoo Daddy will also perform with the NSO Pops.

The season might not yield anything as wild as Ozomatli’s Kennedy Center conga line, but Reineke hopes to push boundaries throughout his tenure.

“I love that we can forever evolve while also retaining the value in the past,” he said. “We’ll still continue to do Tchaikovsky and Dvorak, but we can do Lady Gaga, too. The Great American Songbook is a big, big place. There’s room for so much more.”

“Disney in Concert: Magic Music From the Movies”

Steven Reineke conducts the NSO Pops, 8:30 p.m. Aug. 4 at Wolf Trap, featuring vocalists Candice Nicole, Whitney Kaufman, Aaron Phillips and Andrew Johnson.