Capitals fans congregate on the steps outside the Smithsonian National Portrait Gallery. (Corey Schaefer for The Washington Post)

This used to be a tradition for Pittsburghers, or at least Penguins fans who live here and take pride in the District’s amenities while rooting against its hockey team.

As the Capitals lost to the Penguins during the Alex Ovechkin/Sidney Crosby era, Penguins fans congregated belly-to-belly (like the Antarctic flightless birds they are) on the steps of the Smithsonian National Portrait Gallery and American Art Museum (the two share a building) to jeer at despondent, red-clad locals trudging back down Seventh Street.

And then the Caps won Game 5 of this season’s Eastern Conference semifinals, 6-3, over those same Penguins almost a month ago now. And this time the locals climbed those steps and crowed down at the Pittsburghers: “One more game! One more game!”

Caps fans have kept up the habit after home wins throughout the playoffs, and now it is a tradition for Washingtonians after Capitals victories to mount an impromptu pep rally at the locked gates of an institution of higher learning – a uniquely cosmopolitan celebration of athletic prowess and art.

“How great is it that you can go see a sports game and celebrate portraiture?” said Rebecca Kasemeyer, the gallery’s associate director for audience engagement. “It’s a great way to feel really good about yourself at the end of the night.”

Since the Portrait Gallery and American Art Museum are the rare Smithsonians not located on the Mall, the two like to consider themselves more of a Washington native’s environment than other institutions like the Air and Space or Natural History museums, Kasemeyer said.

Traffic ticks up during lunchtime in the workweek as professionals from nearby offices pop in for glimpses at some of the art. Immediately after work is popular, too, as folks catch another look on the way home. It’s a very Washingtonian way to interact with the Smithsonian.

And as the Caps’ season dragged into the playoffs — in the spring when the weather is nicer — the Portrait Gallery’s courtyard and concourse fill up with red sweaters and T-shirts near puck drop, Kasemeyer said.

“People in the DMV are very fortunate to have the Smithsonian, and they view it as a wonderful resource,” she said. “If we’re going to the Caps game and I had someone in from out of town, I’d say, ‘Let’s get there early because I want to take you to see the courtyard or to see America’s presidents.’ It’s an opportunity to brag and show off all the region has to offer.”

When Caps fans reclaimed the Portrait Gallery’s steps, the museum’s leadership leaned into it.

They’ve boosted staffing around the times hockey fans begin congregating around Capital One Arena. They installed red overhead lights along the Seventh Street stairs for the playoff run. It’s everything the museum can do to entice red rockers to sneak a peek inside before celebrating on the steps later that night.

“I’m guessing that Caps fans are three-dimensional and are engaged and excited about more than just hockey,” Kasemeyer said.

Turns out art geeks, too, are excited about more than portraiture.

More on the Capitals:

At Capital One Arena, a rowdy, joyful Game 2 celebration for Caps fans

Two in the box? Capitals lived through it to put one in the books

Caps fans drove more than 500 miles for the watch party

Ted Leonsis surprises 200 employees with a trip to Vegas to watch the Caps

Game 1 of Stanley Cup finals draws record TV ratings in D.C. and Las Vegas