John Fetterman is a small-town mayor from the Rust Belt of western Pennsylvania, yet much of his strongest appeal is among the urban progressives of big cities like Philadelphia and Pittsburgh.

The 6-foot-8-inch goateed (and bald) native of Reading, Berks County, is a contradiction-in-terms: He abhors the conformity of traditional politics, yet he seeks the biggest stages. He comes from a small town, but is full of big-city ideas. He's a progressive Democrat who received Bernie Sanders' endorsement but looks like he just walked out of a biker bar.

His approach paid off Tuesday. Fetterman, 48, pulled off an upset in the Democratic primary for lieutenant governor. He beat incumbent Mike Stack, a fixture in Harrisburg and Northeast Philadelphia political circles. Stack's manicured look contrasts 180 degrees with Fetterman's blue-collar everyman.

Fetterman will be Gov. Tom Wolf's running mate in the November general election. The two will face off against the Republican ticket of gubernatorial candidate Scott Wagner and lieutenant governor candidate Jeff Bartos, who also secured their victories Tuesday night.

"It's overwhelming," Fetterman told supporters after his victory. He did not wear a suit to the party. "I'm just coming at this from a low-key, overwhelmed, humble place."

Stack left his Election Night party before NBC10 could get comment. His political career was on tenuous ground for the last year. In a bizarre scandal, Wolf ordered an investigation into the treatment of the security detail for Stack and his wife over allegations of mistreatment. It led to Wolf eventually stripping the Stacks of state police protection.

Fetterman's appeal is rooted both in his unusual aesthetic and his progressive politics. The latter has been developed more than the decade he has served as mayor of Braddock, a former steel town in Allegheny County, population 2,100.

He went to the borough in decline with plans to create a non-profit and initiate revitalization efforts. He has credited his roots in central Pennsylvania with keeping him grounded. Before moving to Braddock, he received a master's degree in public policy at Harvard University.

Fetterman first gained traction in Pennsylvania politics when he finished third in the 2016 Democratic primary for the U.S. Senate.

"I just want to take our message of 'All Places Matter,'" he told his supporters. "And I’m so honored by the people of Pennsylvania to be your nominee for lieutenant governor."

During his rise to prominence in the Senate primary two years ago, he was profiled by Rolling Stone, The New York Times and many other news outlets. He appeared on "The Colbert Report." In an interview on NBC10's @Issue program, Fetterman called now-President Donald Trump a "jag-off."

He has Braddock's zip code, 15014, tattooed on one forearm and the names of everyone murdered in the borough since he became mayor on the other arm.

John Fetterman, one candidate running for the Pennsylvania State Senate seat, sits down and talks about his run for state senator. NBC10’s Keith Jones talks to Fetterman about different issues he might come across if elected.