J.D. Gibbs, the elder son of former Washington Redskins coach Joe Gibbs, died Friday at age 49 after a long battle with a degenerative neurological disease.

The news was announced shortly after midnight Saturday by Joe Gibbs Racing, the family-owned NASCAR team that the Hall of Fame coach founded in Huntersville, N.C., in 1991.

“Joe Gibbs Racing appreciates everyone’s respect for the privacy of the Gibbs family during this difficult time,” the statement read, adding that details regarding a memorial service would be announced at a future date.

Within hours of news of his death, the Gibbs family received an outpouring of condolences and support on social media from rival teams, racetrack owners, racers and fans.

Joe Gibbs Racing’s longest-tenured driver, Denny Hamlin, tweeted: “His car. His number. His signature above my door. I will always be grateful for what His family did for mine and the opportunity he gave me 14 years ago.”

From seven-time NASCAR champion Jimmie Johnson: “My heart goes out to the Gibbs family about JD’s passing this morning. He was always so kind and gracious to everyone.”

In the family’s NASCAR business, J.D. was more than his father’s right-hand man. Named president of Joe Gibbs Racing in 1997, J.D. was instrumental in expanding the business from a single-car team to a force in NASCAR that has won four championships at the elite Cup Series level. His younger brother, Coy, 46, also was involved in the team and raced for a time in the NASCAR Truck Series.

Affable and unfailingly optimistic, J.D. Gibbs was warmly regarded throughout NASCAR — held in high regard by corporate executives, racecar drivers, mechanics and media alike.

He took on added responsibilities in 2004 that enabled his father, who had retired as coach of the Redskins after the 1992 season, to return for a second stint as Washington’s head coach.

A devout man and father of four, J.D. graduated from Oakton High in Northern Virginia. He was a rock for his family throughout his own son Taylor’s battle with childhood leukemia. After having the disease diagnosed at age 2, Taylor is cancer-free.

Joe Gibbs had acknowledged his son’s illness during a somber news conference before a NASCAR race at Martinsville Speedway in March 2015. Because J.D. was president of the family’s NASCAR operation, his absence from the track had become a cause for concern.

Gibbs explained that J.D. had been dealing with brain-function problems since late 2014. The cause was unclear at the time, as was the diagnosis. But the symptoms increasingly affected his speech and cognitive function.

“Basically, his situation medically — there’s very few answers,” Gibbs, now 78, told reporters at the time. “We’ve been dealing with this for about six months, and basically what the doctors say is that they really don’t know.

In addition to playing football at William & Mary, J.D. Gibbs raced motorbikes as a child, snowboarded and had a brief career as a stock-car racer. But his father explained during that 2015 news conference that there was no single incident or head trauma that could be linked to his symptoms while acknowledging that “any injury” could have played a part.

Joe Gibbs Racing fields four cars in the Cup Series (for drivers Hamlin, Kyle Busch, Martin Truex Jr. and Erik Jones) and three in the Xfinity Series, one rung down. It also funds development programs for a handful of young drivers.