IndyCar made the announcement at Indianapolis Motor Speedway.
Wilson, a British driver who lived outside Denver in Longmont, Colorado, was hit in the head during Sunday's race by piece of debris that had broken off another car. Wilson's car veered into an interior wall at the track, and he was swiftly taken by helicopter to a hospital in Allentown, Pennsylvania.
IndyCar driver Justin Wilson has died after sustaining a severe head injury at Pocono Raceway yesterday. He was 37. pic.twitter.com/YxvN2zo6p2— SportsCenter (@SportsCenter) August 25, 2015
"Can't even begin to describe the loss I feel right now. He was my Brother, my best friend, my role model and mentor. He was a champion!" his younger brother, Stefan, also an IndyCar driver, tweeted. Stefan Wilson said his brother's organs would be donated.
The last IndyCar driver to die from an on-track incident was Indianapolis 500 champion Dan Wheldon, who was killed in the 2011 season finale at Las Vegas after his head hit a post in the fence when his car went airborne.
After Wheldon's death, Wilson became one of three driver representatives to serve as a liaison between the competitors and IndyCar. It was no surprise: The 6-foot-4 Wilson, easily the tallest in the series, was well liked.
"Justin's elite ability to drive a race car was matched by his unwavering kindness, character and humility - which is what made him one of the most respected members of the paddock," said Mark Miles, CEO of Hulman & Co., the parent company of IndyCar and Indianapolis Motor Speedway.
Wilson won seven times over 12 seasons in open-wheel racing and finished as high as fifth in the Indianapolis 500. An acclaimed sports car racer, Wilson won the prestigious 24 Hours of Daytona with Michael Shank Racing, and he competed in 20 Formula One races in 2003 before moving to the U.S. to join Champ Car.
He finished third in the Champ Car standings in 2005, and was runner-up in both 2006 and 2007. To support his career, his management team in 2003 created a program that allowed fans to invest in the driver. Hundreds of people bought shares in Wilson, who was dyslexic and a strong supporter of foundations related to the disorder.
Wilson, a native of Sheffield, England, entered this season without a full-time ride. He latched on with Andretti Autosport and was in the sixth of seven scheduled races with the team. The agreement began as a two-race deal for events at Indianapolis Motor Speedway, and then was increased to the final five races of the year. The IndyCar season concludes Sunday in Sonoma, California.
Andretti Autosport called Wilson "a tremendous racer, a valuable member of the team and respected representative to our sport."
"While Justin was only part of the Andretti lineup for a short time, it only took a second for him to forever become part of the Andretti family," the team said. "His life and racing career is a story of class and passion surpassed by none. Our thoughts and prayers remain with the Wilson family and fans worldwide. Godspeed, JW."
Wilson finished a season-best second at Mid-Ohio in early August. He said after the race that he raced clean and did not take any risks that would have jeopardized eventual race-winner Graham Rahal because Rahal was part of the championship race and Wilson was not.
"Anyone who follows our sport knows Justin was one of the most well-respected, highly regarded and loved people in the entire paddock," said Miles, who passed on the Wilsons' gratitude to the IndyCar safety team and medical staffs of the series, Pocono Raceway and the hospital in Allentown.
The family also was grateful to the entire motorsports industry.
"Particularly the Wilson family wishes to thank Justin's fellow drivers, and their families, who have been so thoughtful, and kind, and supportive," Miles said.
Ed Carpenter, the only driver/owner in IndyCar and the stepson of IndyCar founder Tony George Jr., attended the announcement and spoke of the respect Wilson had throughout the paddock.
"Days like this are extremely hard on all of us," Carpenter said. "Justin was a great professional driver and extremely good at his craft. Beyond that, he was a great guy. One of the few, if only, guys who really was a friend of everyone in the paddock. Everyone respected him for the way he carried himself."
Wilson broke a bone in his back at Mid-Ohio in 2011. He missed the final six races of the season and wore a back brace for more than two months while he was restricted from any physical activity. The injury kept him out of the season finale at Las Vegas, the race where Wheldon died. He also broke his pelvis and suffered a bruised lung in the 2013 season finale at Fontana.
Wilson once said that his injuries and Wheldon's death did nothing to change his perspective or make him question his career choice.
"You've got to know the risks and work out if those risks are acceptable," Wilson told The Associated Press upon his return to racing in 2012. "To me, it's acceptable. But I'm not going to stop trying to improve it. All the drivers, this IndyCar, we're always trying to make it safer, but at the end of the day, it's a race car. We're racing hard, we're racing IndyCars and it's fast. When it goes wrong, it can get messy."
In addition to his wife, Julia, Wilson is survived by two daughters, 7 and 5. The family asked for donations to a trust fund for his daughters in lieu of flowers.