While the famous folks were showing off their golden hardware in Hollywood on Sunday, Seth Hurwitz, owner of the 9:30 Club, was toasting his own movie moment.

The veteran concert promoter turned sometimes actor can be seen (and heard) in the opening scene of the Oscar-winning film “Green Book.” But more than a few of the close friends attending Hurwitz’s Oscar party in Washington had no clue their host was a part of the magic.

“Wait, that was you? No way,” Hurwitz, who still can’t believe his own luck, recalled them saying. After years of sending off audition tapes in between promoting big-name concerts at 9:30, the Anthem and Merriweather Post Pavilion, as well as other local venues, Hurwitz’s big-screen debut (he plays a mobster and has one line in the opening scene with star Viggo Mortensen) is in a movie that just won the Academy Award for best picture.

“I’m doing all right, I guess,” said the 60-year-old, who has no formal theater training and considers himself a natural.

Just how does one go from running one of the most popular concert venues in the country to starring opposite an A-lister? Well, it helps to have famous friends.

Hurwitz got started with a bit part in “Treme,” the HBO series about New Orleans co-created by his good pal George Pelecanos. He said he scored the 2010 cameo “because [Pelecanos] realized I wouldn’t leave him alone until he did.” That part led Hurwitz to casting director Meagan Lewis, who over the past decade has sent Hurwitz occasional roles to consider — mostly on cop shows.

He sent in tape after tape and rarely heard anything back. But he kept at it. “I’m used to being in the driver’s seat,” Hurwitz said. “This has been an amazing lesson for me in humility because you can’t negotiate your way in here, you can’t charm your way in. You have to act your way in.”

Eventually Lewis sent him the script for “Green Book,” and he had one thought: “I have no chance in hell of getting this.” But why not? He shipped off his audition and waited. And waited. Then, he had a chance lunch with Washington Wizards owner Ted Leonsis, who also happens to be good pals with “Green Book” director Peter Farrelly, and got his name to the man in charge. And poof.

“I’m going to say I owe it to Ted,” Hurwitz said.

He saw “Green Book” for the first time on opening day at the movies, like everybody else, and had one critique — his scene got cut down. Everyone else’s take? “You’re in the movie, shut up.”

Despite his big break, Hurwitz doesn’t plan to switch careers anytime soon. But he also doesn’t plan on stopping. There’s a rush that comes after the director yells “Action” that Hurwitz likens to jamming onstage at a concert.

“When you hear that clap, that’s just fantastic. It’s a dare,” Hurwitz said. “There’s no way out except to act, and I live for that sort of thing.”