In the fall of 2005, O'Quinn was a contestant on Roush Racing: Driver X. He was ultimately runner-up in the competition, but skipped the Craftsman Truck Series and proceeded directly to the Busch Series with Driver X winner Erik Darnell being inked to the Roush truck contract.

In 2006, he raced the World Financial Group No.
50 Ford in the Busch Series.
He got his first Top-10 finish at Nashville Superspeedway after starting second, and followed it up with Top-10s at  Milwaukee, ORP, Memphis and Charlotte, where he scored a career best finish of 5th.

O'Quinn was named Busch Series Rookie of the Year after the 2006 Season Finale at Homestead-Miami Speedway beating former NASCAR Winston Cup driver John Andretti and teammate Todd Kluever, among others, for the award.
In 2007, O'Quinn made occasional starts in No.
17 Dish Network Ford and also ran part-time with Mac Hill Motorsports in the No.
56 Chevy.

After driving part-time in 2007 in selected races with Roush Fenway Racing.
O'Quinn announced his departure from the team, due to a lack of sponsorship which prohibited from landing a full-time ride with the team.
He then signed on to drive the No.
56 Chevy for Mac Hill Motorsports part-time for the remainder of the year.
He made only one start in 2008 for Mac Hill, where he finished 28th at Richmond.
He ended the year driving the No.
35 Team Rensi Motorsports Ford on a part-time basis, with a best finish of 40th.
He signed with JD Motorsports in 2009, and drove the No.
01 Sun Drop Chevrolet Impala.
Following the Food City 250 on August 21, 2009, O'Quinn left the JD Motorsports team.
He finished the year by start and parking for K-Automotive Motorsports and Fitz Racing.
In 2011, O'Quinn joined Go Green Racing, where he ran five races.

After O'Quinn's NASCAR career stalled, he moved back to Virginia to help run the family trailer business.
O'Quinn also occasionally raced at the Lonesome Pine Raceway.
In the fall of 2005, O'Quinn was a contestant on Roush Racing: Driver X. He was ultimately runner-up in the competition, but skipped the Craftsman Truck Series and proceeded directly to the Busch Series with Driver X winner Erik Darnell being inked to the Roush truck contract.
In 2006, he raced the World Financial Group No. 50 Ford in the Busch Series. He got his first Top-10 finish at Nashville Superspeedway after starting second, and followed it up with Top-10s at  Milwaukee, ORP, Memphis and Charlotte, where he scored a career best finish of 5th.
O'Quinn was named Busch Series Rookie of the Year after the 2006 Season Finale at Homestead-Miami Speedway beating former NASCAR Winston Cup driver John Andretti and teammate Todd Kluever, among others, for the award. In 2007, O'Quinn made occasional starts in No. 17 Dish Network Ford and also ran part-time with Mac Hill Motorsports in the No. 56 Chevy.
After driving part-time in 2007 in selected races with Roush Fenway Racing. O'Quinn announced his departure from the team, due to a lack of sponsorship which prohibited from landing a full-time ride with the team. He then signed on to drive the No. 56 Chevy for Mac Hill Motorsports part-time for the remainder of the year. He made only one start in 2008 for Mac Hill, where he finished 28th at Richmond. He ended the year driving the No. 35 Team Rensi Motorsports Ford on a part-time basis, with a best finish of 40th. He signed with JD Motorsports in 2009, and drove the No. 01 Sun Drop Chevrolet Impala. Following the Food City 250 on August 21, 2009, O'Quinn left the JD Motorsports team. He finished the year by start and parking for K-Automotive Motorsports and Fitz Racing. In 2011, O'Quinn joined Go Green Racing, where he ran five races.
After O'Quinn's NASCAR career stalled, he moved back to Virginia to help run the family trailer business. O'Quinn also occasionally raced at the Lonesome Pine Raceway.
Danny O'Quinn Jr.