This post is based on reporting by the Associated Press.

The man who ousted a powerful Democratic congressman in a doozy of a primary election stunner is a guitar-playing, twice-arrested former city councilman who advocates legalizing marijuana .

Beto O’Rourke kept a low profile Wednesday after defeating U.S. Rep. Silvestre Reyes in the El Paso district. The former House Intelligence chairman, meanwhile, returned to Washington after being denied even a runoff despite an endorsement from President Barack Obama and a campaign stop from former President Bill Clinton.

The upset was a twist on the anti-incumbent fervor that swept through the U.S. House in the 2010 midterms. Then, it was Republicans swinging a wrecking ball to entrenched Democrats, but on Tuesday, O’Rourke ousted an eight-term congressman and fellow Democrat who he had attacked as becoming too cozy and ineffective to stay in Congress

At least that was the message in public. Behind the scenes, O’Rourke was embroiled in one of the nastiest U.S. House races nationwide this primary season.

Ads played up Reyes’ ties to a company that was awarded a $200 million contract and gave Reyes contributions and hired his children, while Reyes shot back with television spots recounting O’Rourke being arrested for drunk driving and showing a cellphone video of O’Rourke rolling around on a barroom floor.

“It was a very tough campaign. We both worked hard, but at the end of the day I respect him and I thank him for his service,” said O’Rourke, adding that he welcomed Reyes’ offer of assistance in the transition.

O’Rourke is unlikely to face much of a threat from the GOP nominee in the heavily Democratic district this November.

He was an unconventional candidate for being such a serious threat to an establishment incumbent like the 67-year-old Reyes.

O’Rourke has supported the idea of legalizing marijuana as a way of making a dent in the drug war being waged directly across the border from El Paso in violent Ciudad Juarez. O’Rourke, however, said during his campaign that he would not press for legalization in Congress because it wasn’t a priority to this district.

He’s also a former guitarist in an El Paso rock band that included members who now play in the Grammy Award-winning act The Mars Volta. He was arrested in the 1990s on charges of burglary and drunk driving, and has called his public service a way for atoning for those mistakes. O’Rourke said the burglary arrest happened after he tripped an alarm while jumping a fence at the University of Texas at El Paso in 1995 but prosecutors declined the case. As for the drunken driving arrest, he ays he received deferred adjudication 15 years ago and was not convicted but calls the incident “a mistake.”

But O’Rourke also comes from a family with deep political roots. His father, Pat O’Rourke, was a former El Paso County judge who was a popular longtime Democrat before switching parties in 1996, when he unsuccessfully ran for Congress as a Republican.

A super PAC called the Campaign for Primary Accountability spent $240,000 on ads that linked Reyes to a controversial contract awarded to a company that gave him campaign contributions and hired his children, spokesman for the super PAC Curtis Ellis said.

Gregg Rocha, a political science professor at the University of Texas at El Paso, said voters care less about the missteps in O’Rourke’s personal life than the corruption scandal that has been weighing on the city.

Reyes’ defeat assures that Texas will lose a member of its Hispanic delegation. Texas was awarded four new U.S. House seats because of a population surge the last decade driven by Hispanics, whose numbers grew by 2.8 million in the last decade — second only to California.

Texas, however, hasn’t elected more than six Hispanics to Congress since 1997. The majority of the voting-age population in two of the new districts is Hispanic, but the only Hispanic candidate remaining in those races is Domingo Garcia, who faces a runoff with state House Rep. Mark Veasey in newly created 33rd Congressional District.