Washington has always been a city of great crowds surging through its avenues, swirling across its vast grassy mall; crowds who have come for protest, for celebration, for funerals and, yes, even for inaugurations – big and small.

But never for sports, not at least since Washington’s NFL team won three Super Bowls between 1983 and 1992. DC is a government town, and sports never seemed to fit the image.

That changed every night of hockey’s Stanley Cup finals, as fans came, wearing red hats, red shirts and carrying signs that said “Rock The Red”.

At first the crowds started small, but within a few hours, a crimson river snaked around the Capital One Arena, lapping at the steps of the National Portrait Gallery. All because the red-clad Washington Capitals were on the big screen, and on the verge of the city’s first professional sports championship in 26 years.

Game 5 on Thursday night ended in elation for them as the Capitals won the Stanley Cup with a 4-3 come-from-behind win in Las Vegas. Back in Washington, Capitals fans celebrated into the night.

Despite the city’s championship drought, Washington sports fans are often not described as “long-suffering” or “resilient” or “downtrodden” as they are in other cities. Mostly because the national perception of DC has been that it isn’t a sports town at all – too consumed with politics and other important business to care about anything else. It’s a sense so ingrained in the area’s identity that seven years ago the Washington Post raised the question: “Why is Washington DC a mediocre sports town?”

“I would say we are a good sports town – we just don’t have the attitude and aggression that New York and Philadelphia fans have,” Christopher Sargent, who has lived his 40 years in the Virginia suburbs and is a passionate fan of all of DC’s teams.

Something is changing, though and, it’s not just the Capitals’ Stanley Cup run. Suddenly the sports city that never was a sports city is popping up in headlines worldwide. Next month, the Washington Nationals will host baseball’s All-Star Game at their stadium, which is only three blocks from Audi Field, the new ground for Major League Soccer’s DC United, who appear close to acquiring Wayne Rooney. There appears to be an excellent chance England’s leading scorer could be with the United team for the stadium’s mid-July opening.

Capitals captain Alexander Ovechkin celebrates with the Stanley Cup. Photograph: Dave Sandford/NHLI via Getty Images

And while all of this might seem coincidental, it is not. What is happening now is part of a slow build over the past 15 years, designed to make Washington what it has become: a sports city.

“Mayor Bowser likes to say: ‘This isn’t your grandfather’s Washington DC,’” Mayor Muriel Bowser’s chief of staff, John Falcicchio, told the Guardian this week.

The new interest in sports is a big part of that, he added.

Two decades ago, DC had only an NFL team inside their borders. Its hockey and basketball teams played in an arena located along the Beltway in Landover, Maryland. There was no baseball team, following two failed attempts – the last of which ended in 1971. But then the Capital One Arena opened in 1997, bringing the Capitals and the NBA’s Wizards into the city, and then baseball moved the Montreal Expos to town in 2005, prompting the building of Nationals Park. Now only the NFL team is left out, having moved in 1997 to the same area where the basketball and hockey teams had played.

“What we are looking to do is diversify our economy,” Falcicchio said, speaking about a general policy over four regimes of DC mayors to lure sports teams and big sports events to town. “What we are looking to do is find ways to capture more tourists, and sports is a key driver – we kind of have something for everyone. It has given a vibrancy to our city.”

Sargent said: “That’s part of the experience of a fan here now, going into the city to see DC sports teams representing DC.”

If DC can find a place for an NFL stadium, DC will have five major sports teams – an amazing number for a city of 68 sq miles

None of this has come cheap. Washington has spent more than $700m of public money on pro sports facilities, this century and is looking to throw more at taking the RFK Stadium site (the NFL team’s old home stadium), not far from the Capitol building, as a possible location for new football stadium. A cost the mayor’s office feels is worth it, because the new stadiums have allowed developers to invest in huge new buildings filled with offices, hotels, apartments and restaurants. All of these developments, they insist, bring jobs. An example is the new Wizards practice facility and arena for the WNBA’s Mystics, that is being built on an abandoned portion of the St Elizabeth’s mental health hospital in Ward 8, one of the city’s poorest neighborhoods.

“We’re excited about the jobs that will create,’’ Falcicchio said.

It’s a steep price to be considered big-league, and one not without risks. Many sports economists have warned that building sports stadiums and chasing big events (which DC has in recent Olympics and World Cup bids) might create a buzz but doesn’t always translate into value.

“Professional sports teams create very few full-time-equivalent jobs for local residents,” Victor Matheson, a Holy Cross sports economics professor said. “An NFL team employs local game day workers, but that works out to fewer than 100 full-time jobs, and these are minimum wage jobs. Only a few jobs go to locals: sales, marketing, lower-level administration. A typical Macy’s department story will hire more local workers than an NFL team. Plus, given the fact that DC is a large, super-rich metro area, the area is super desirable [for sports teams] – even without subsidies.”

American cities have been building themselves around professional sports for decades now. DC, in many ways, is following a well-used blueprint. Some have had success, too. Matheson pointed to Indianapolis, which used the Colts’ move from Baltimore in 1984 to cast the city as a top destination for events like the Super Bowl and college basketball, eventually convincing the NCAA to move its headquarters there. Another, he said, is Los Angeles, which has used existing facilities and private financing to take on the 2028 Olympics and absorb 10 professional sports teams in Los Angeles and Orange counties.

Wayne Rooney: Washington-bound? DC United want the Everton forward to join them in MLS. Photograph: Paul Ellis/AFP/Getty Images

Washington, he added, is not a city that needs to embrace sports to be relevant.

“If you need an MLS team to find DC on a map, you really need a new map,” he wrote.

But if DC can find a place for an NFL stadium, the city will have five major pro sports teams inside its borders. An amazing number for a city that is just 68 sq miles and has vast swaths of federal parks and monuments. The major impediment might be a 2013 district council resolution that demands the NFL team change their team name from “Redskins” – which the council called “insulting and debasing”. The team owner, Daniel Snyder, has refused to consider a name change.

When asked about the name issue, Falcicchio said: “The council has weighed in on the name and we are focusing on what the [RFK] site can be.” He also said: “The last time the NFL team won they were in Washington.”

Not the suburbs.

A clear message that the sports town that was never a sports town is trying hard to really be a sports town.