Carrie Brownstein rehearses a new track for “Portlandia,” an upcoming show on IFC. Brownstein, a guitarist and singer from the defunct Portland rock band Sleater-Kinney, stars in the new comedy, which she helped conceive.

In the music video that kicks off “Portlandia,” a new comedy series making its debut Jan. 21 on IFC, Fred Armisen walks the streets of Portland, singing to a flat, synthesized soundtrack and praising the city as a flannel-clad slacker’s paradise where “young people go to retire.” As Armisen marches along the Willamette River waterfront, he is joined by stylish women wearing vintage eyeglasses, bearded men in leather jackets, circus clowns and finally by his co-star, Carrie Brownstein, who arrives with several facial piercings.

This is when Armisen halts the impromptu parade and warns Brownstein that her look is “a little San Francisco,” relieving her of a nose ring and a pair of earrings before allowing the march to proceed.

It is always a risky proposition when anyone tries to codify the spirit of a proudly independent, nonconformist scene. (And in this case Armisen, a nine-season veteran of “Saturday Night Live” and resident of New York, would seem to have less of a claim to it than Brownstein, a guitarist and singer from the Portland rock band Sleater-Kinney, which broke up in 2006.)

But together Armisen and Brownstein, two guileless if unlikely collaborators, hope they possess enough street cred to serve as ambassadors of Portland’s counterculture and to present their version of it, in “Portlandia,” to an audience beyond the Pacific Northwest.

“It’s not funny or that interesting to make a documentary about Portland,” Brownstein said in an interview alongside Armisen as they worked on the postproduction of “Portlandia.” “One’s interpretation of it is far more magical and curious than what actually exists there.”

Armisen, a former drummer in the Chicago rock band Trenchmouth, made his move to comedy several years ago, helped along by a satirical video he made at the 1998 South by Southwest music festival. Though he is now the resident impersonator of President Barack Obama at “SNL,” he has never lost his connection to the alternative scene.

In recent years he befriended Brownstein and often visited her in Portland, a city whose outsider appeal even he has trouble quantifying. “I liked that it wasn’t too sunny,” Armisen said. “I like wearing jackets. It was a place I could walk around in my little jacket.”

Armisen and Brownstein also began experimenting with short videos that they posted online under the name ThunderAnt. An uncertainty about whether their partnership was essentially comedic or musical can be seen in some early efforts, like a video in which Brownstein interviews Saddam Hussein, portrayed by Armisen as an aging, British rock star with a Pete Townshend-esque accent. (“Which is obviously musical,” Brownstein said with some sarcasm.)

The goal of the ThunderAnt segments, Armisen said, wasn’t to “have any punch lines or jokes or anything — just weird, awkward moments, and not even awkward to be funny.” But as their video repertoire slowly grew, a shape and a voice began to emerge for a television series that Armisen proposed in late 2009 to Lorne Michaels, the creator and executive producer of “Saturday Night Live.”

For Brownstein, who does not come from a professional comedy background, making “Portlandia” meant overcoming a self-consciousness about creating in a group setting, even if it occasionally reminded her of her rock ’n’ roll exploits in Sleater-Kinney.

“I did recall those slightly heartbreaking, embarrassing moments,” she said, “where you bring in a little bit of a song and you’re just met with stares, and you realize maybe you should have kept that idea at home. With comedy writing, that’s happening 100 times as fast.”

Months later Brownstein still sometimes describes herself as “an imposter” on “Portlandia” and says her primary role on the show is to serve as “the rain stick, the didgeridoo — some little thing that’s just there so people remember it really is taking place in Portland.”

Armisen, meanwhile, recognized his involvement in a sketch-comedy side project would inevitably raise questions about whether he is leaving “Saturday Night Live,” a route he said he is not currently considering. For comparison, Armisen mentions Beck, a rock musician who walks a similarly erratic career path and whose major label contract allowed him to continue to release independent albums. “Both seemed to work well together,” he said. “I think they can coexist.”

The show’s creators are also bracing for reaction from the citizens of its namesake city. But Brownstein said that for sheer unpredictability the characters of “Portlandia” could never surpass Portland itself.

“The strange thing we all noticed,” she said, “is no matter how far out on a limb we went, we always ran into that person within two days.”

For example, Brownstein said, “the night we wrapped the pilot, the options were: Go out to dinner, or we could watch a completely naked bike ride through the city.”