( Matt Volz/AP Photo)

Montana has never seen a Democratic U.S. Senate candidate like state Rep. Amanda Curtis.

Selected by state Democrats last week to replace Democratic Sen. John Walsh on their November ticket after a plagiarism scandal derailed his re-election bid, Curtis is a far cry from the centrist candidates the party tends to field for statewide office in Big Sky Country.

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Curtis, a 34-year-old math teacher with a nose ring and a background in labor activism, has only one term in the state legislature to her name, and told ABC News she plans to run a progressive, "grassroots" campaign on income inequality and student-loan debt.

"Washington could be fixed if we send more working-class Americans to D.C., so the system can start working for us and not against us," said Curtis, who would be Montana's first female senator. (In 1916, Montana sent Jeannette Rankin, the nation's first female representative, to Washington.)

She has impressed Montana Democrats with her youth and energy. In 2013, she kept a YouTube video diary of her first legislative session, which made the rounds in Montana political circles.

"[Walsh] was the establishment's choice, but he didn't make rank-and-file activists feel good about being Democrats; Curtis does," Montana Democratic political blogger James Conner said in an email.

"He's a pleasant fellow who generates the excitement of a bowl of cold noodles. Curtis is a chili pepper," he added.

Her campaign is just a few days old, but Curtis has lined up endorsements from two of Montana's largest unions and Democracy for America, a national progressive group that wasn't involved in Walsh's re-election race.

"She's refreshing, she's a woman and she's an educator," Montana State University political scientist David Parker said. "She gets Democrats excited about voting."

But Montana is a conservative state even on the left. A 53-year-old Iraq War veteran and former lieutenant governor, Walsh was running a traditional campaign on reducing the deficit and veterans' issues before a New York Times report that he had plagiarized his master's thesis forced him from the race.

The state's other senator, Democrat Jon Tester, ran and won office as a centrist in 2006 and 2012. He is viewed as one of the more conservative Democrats in the U.S. Senate. Dan Kully and Brandon Hall, two strategists who worked on Tester's last bid and Walsh's reelection campaign, have not joined the new campaign.

While she called Tester as a role model and "pretty damn cool," Curtis has rallied against Montana's Democratic establishment in the past. An advocate for gun control, she attended a 2013 Mayors Against Illegal Guns Rally to pressure Democratic Sen. Max Baucus to support expanding background checks.

Conservatives have pounced on her writing in a socialist newsletter, along with her video diary. In one entry, she said she had to stop herself from "walking across the floor" to "punch" Republican legislators who voted to make gay sex illegal in Montana. In another, she wore a hooded sweatshirt to commemorate the death of Trayvon Martin.

She defended the video diary, and accused Republicans of "taking words out of context."

"Anyone who wants to can go to YouTube and see every single video for themselves," Curtis told ABC News in a phone interview this week.

But she appears to be learning from the experience. When asked for her thoughts on the shooting of African-American teen Michael Brown in Ferguson, Missouri, by a police officer, Curtis said she's "not ready to talk about that," only adding that she "absolutely" had feelings on the killing.

With only 74 days until the election, Curtis faces an uphill challenge, even if she has Democrats excited. Walsh was already trailing Republican challenger Rep. Steve Daines in polls before the scandal surfaced.

"The chances are slim," Parker said. "The cases are few and far between when a candidate goes into an election facing such odds and pulls it off."

She may fall short in November, Parker added, but this race may not be Curtis's last.

"The biggest thing for Amanda Curtis is to run a competent campaign, to make it close and position herself for the future," he said.