Wilson, 37, had been in a coma since Sunday, when a piece of debris from another racer's car struck his helmet on the final laps of the “Tricky Triangle” at Pocono Raceway in the penultimate IndyCar Series race of the season.
Loved ones of the Sheffield-born Andretti Autosport racer had flown to be at his bedside at Lehigh Valley Health Network Cedar Crest Hospital in Allentown earlier on Monday before his death was announced.
Wilson's family said in a statement that he was a "loving father and devoted husband, as well as a highly competitive racing driver who was respected by his peers".
Wilson's younger brother Stefan, also a racing driver, paid tribute on Twitter.
“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!” he wrote.
“I often told him, I just want to grow up to be half the man he is, as that will make me a pretty good man.”
Mark Miles, chief executive of the parent company which runs IndyCar and the Indianapolis Motor Speedway, said: “This is a monumentally sad day for IndyCar and the motorsports community as a whole.
“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.”
Andretti Autosport also paid tribute, describing Wilson as a “tremendous racer, a valuable member of the team.”
“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,” a statement said.
“His life and racing career is a story of class and passion surpassed by none.”
TRIBUTES FROM MOTORSPORT LEGENDS
Formula One great Nigel Mansell wrote on Twitter: “Terrible news... deepest condolences to all the family. RIP.”
IndyCar legend Dale Earnhardt Jr added: “Thoughts and prayers to his family, friends, and to the @IndyCar family. #RIPJustinWilson”.
Other drivers paid tribute to Wilson's personal qualities.
Danica Patrick wrote: “Wow, what a sad day. @justin_wilson was a good man. A great man. I had the pleasure of knowing him and pray for his family.”
Former team-mate AJ Allmendinger added: “We lost one of the great ones today. One of the best ever.”
Wilson had driven in major US open-wheel racing since the 2004 season. He was driving a partial schedule in 2015 for Andretti, making his 174th IndyCar start. He recorded seven wins in CART and IndyCar races, his most recent coming at Texas in 2012.
New Zealander Scott Dixon, who won the Indy 500 in 2008 from pole position, tweeted: "Father, Husband, Friend, just an amazing human being. We will miss you to no end. Love to the Wilson Family. #RIPJustin."
Brazilian Tony Kanaan, winner of the 2013 Indy 500, posted on Twitter: "Why do we do this? Because we love it, don't want to be anywhere else but a race car. We will keep your legacy my friend. Racers race."
‘SAFETY A CONTINUOUS PROJECT’
Wilson was hit by the nose cone of fellow driver Sage Karam's car after it spun out on lap 179 of the 200-lap race.
The father of two was airlifted to hospital immediately after the crash, but never regained consciousness.
Wilson's death was the first fatality in IndyCar since the 2011 accident that claimed the life of fellow Briton Dan Wheldon, the 2005 IndyCar Series champion and a two-time winner of the Indianapolis 500.
Former racer Eddie Cheever, now an IndyCar analyst for ESPN, said Wilson's death should lead to a thorough analysis of safety measures in the sport, while acknowledging the freak nature of Sunday's accident.
“Safety is not one of those things that because you have a clear record for a certain amount of time that you stop doing development,” he said.
“It is time solutions are looked for and it’s time that the drivers got together and came up with a few ideas and I sincerely hope that some progress will be made on this issue.
“Safety is a continuous project, and in the past, IndyCar has done a very good job of doing it. But this is something they are going to have to focus on more than they have done in the past.”
Since 1966 there have been 18 deaths in IndyCar (which includes the series' previous incarnations as Champ Car, CART and Indy Racing League). Eight alone have come at the famed Indianapolis Motor Speedway and all but two on ovals.
American motor racing legend Mario Andretti siad in 2014. "I think IndyCar has been at the head of the safety) curve. There is not a sanctioning body more concerned with safety than IndyCar.
"But on an oval you have the speed, Formula One doesn't come close to those type of speeds and then you have cars side-by-side at 370km/h.
"In a nutshell, IndyCar is definitely more dangerous because of the ovals so they are dealing with a totally different monster."
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Original source: Motorsport mourns Justin Wilson