In a stunning move two days before the season-opening Daytona 500, NASCAR said Busch would not be allowed to participate in any series activities until further notice given the "serious nature of the findings and conclusions" made by a Delaware judge involving the driver known as "The Outlaw."
"Kurt Busch and his Stewart-Haas Racing team are fully aware of our position and why this decision was made," NASCAR said in a statement. "We will continue to respect the process and timetable of the authorities involved."
Busch attorney Rusty Hardin said the driver will appeal, and NASCAR said it will be expedited.
"We assure everyone, including NASCAR, that this action against Mr. Busch will turn out to be a travesty of justice, apparent to all, as this story continues to unfold," Hardin said in a statement. "It is important for everyone to remember that the Commissioner's report has to do with a civil, family law matter and no criminal charges have been filed against Mr. Busch.
"We ask everyone's patience as this case continues in the court of law and are confident that when the truth is known Mr. Busch will be fully vindicated and back in the driver's seat."
Busch becomes the first driver suspended by NASCAR for domestic violence. Chairman Brian France had maintained the series would let the process play out before ruling on Busch's eligibility — and the series came down hard in finding that he committed actions detrimental to stock car racing and broke the series' behavioural rules.
Travis Kvapil, who qualified second for Friday night's Truck Series race, was arrested and charged with assault of his wife in 2013. NASCAR took no action against Kvapil.
Chevrolet immediately suspended its relationship with Busch. A short time later, on the glass outside of Busch's garage stall at Daytona, someone had scrawled in black marker "#41 Ray Rice," a reference to the former Baltimore Ravens running back whose own case of domestic violence dominated much of last year. Busch drives the No. 41 Chevrolet.
In a 25-page opinion explaining why he issued the no-contact order this week, Family Court Commissioner David Jones concluded that it was more likely than not that Busch abused Patricia Driscoll by "manually strangling" her and smashing her head into a wall inside his motorhome at Dover International Speedway last September.
The 36-year-old Busch has denied the alleged assault, which is the subject of a separate criminal investigation, but the judge said Driscoll's version of the incident was more credible than Busch's.
Driscoll said she was never motivated to have Busch punished by NASCAR.
"I reported a crime, just like anybody else who has been abused should do, because no one is above the law," Driscoll said. "I'm very encouraged that NASCAR is taking steps to recognize that domestic violence is a serious issue, and I hope that we see them develop a very clear policy on it."
She urged NASCAR to develop a confidential reporting mechanism that partners of drivers could use to report domestic abuse without fear of threats or reprisals for coming forward.
"NASCAR has made it very clear to our entire membership and the broader industry that any actions of abuse will not be tolerated in the industry," NASCAR executive vice-president Steve O'Donnell said. "I want to make it clear that any inference that there's a culture or a tolerance for this type of behaviour is patently false."
It is Busch's third career suspension. He was suspended in 2012 by NASCAR for threatening a reporter, and parked for the final two races of the 2005 season by Roush-Fenway Racing after he was pulled over by police in Arizona.
He now races for SHR, which has not said who will replace Busch in Sunday's race.
"We are in the midst of finalizing our plans for the Daytona 500 and we will announce those details as soon as we're ready," SHR said.
Busch, the 2004 NASCAR champion, has 25 career wins but only one since 2011. It came last year, his first season with SHR, the team that helped resurrect his career.
Team co-owner Gene Haas hand-picked Busch to drive a car paid for out of pocket by Haas because the machine tool manufacturer wanted to see a driver take his company to victory lane. Busch was fired at the end of 2011 by Roger Penske for a series of on- and off-track incidents, and he spent two seasons driving for low-budget teams before Haas extended the olive branch.
Busch had been on a resurgence of sorts at SHR, which allowed him to compete in both the Indianapolis 500 and the Coca-Cola 600 on the same day last year. He finished sixth at Indianapolis last May and was named rookie of the race.
But his season began to unravel late last summer as his performance tailed off. Although he made the Chase for the Sprint Cup championship, he was eliminated after the first round.
It was the weekend of the first elimination race, at Dover, where Driscoll alleged Busch assaulted her in his motorhome.
She said she drove to the track out of concern for Busch, who sent her alarming text messages following a poor qualifying effort. She said the two argued in the bedroom section of the motorhome before he slammed her head against a wall three times.
Driscoll did not file charges until November, and the Delaware attorney general has not decided if Busch will be charged.
But Driscoll sought a no-contact order, and the couple spent four days over December and January in a Delaware court presenting their sides. At one point, he accused of her of being a trained assassin.
Jones noted that Driscoll presented false testimony that conflicted with that of a chaplain who saw her immediately after the alleged assault and said he didn't see any marks or bruises on her. Jones nevertheless said he didn't believe Driscoll's false testimony amounted to perjury or intentional falsehood.
The judge concluded that Busch did not appear to be a prototypical batterer who uses violence to subjugate or control, but that the incident instead was most likely a "situational" event in which Busch was unable to cope and to control his tendency to act out violently in response to stress and frustration, causing him to "snap."
At the same time, however, Jones said he believes there's real possibility that Busch will lash out again. Jones added that because Busch has a propensity to lose control in response to disappointing or frustrating situations involving racing and that those who love him are likely to be around him at those times "there is a substantial likelihood of acts of domestic violence by respondent against future intimate partners."
Busch's attorneys filed a motion Thursday asking Jones to re-open the hearing so that they can present testimony from three acquaintances of Driscoll who they say were previously reluctant to get involved but have now come forward to contradict statements Driscoll has made about her relationship with Busch.
Associated Press writer Randall Chase contributed to this report.