JD Vance called Busch "one of NASCAR's greatest racers."
NASCAR CEO Steve O'Donnell expressed deep sorrow, describing Busch as "an American badass."
"We certainly had our battles but I would give a lot of money to have a few more battles," O'Donnell said.
Prior to his medical emergency, Busch had been dealing with a suspected sinus cold during the event at Watkins Glen on May 10, where he requested medical assistance after the race.
He subsequently rebounded to win the Trucks Series race at Dover before securing a 17th-place finish at the All-Star race.
Fellow competitor Brad Keselowski noted that Busch had shown signs of physical illness, but his strong performances temporarily eased concerns.
"But then when he ran the Truck race last week, those [thoughts] were honestly kind of erased in my mind," Keselowski said.
According to the Centers for Disease Control and Prevention, sepsis is an extreme response to an infection that causes the immune system to damage its own tissues and organs.
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All 39 drivers scheduled for the upcoming race will carry a black No. 8 decal on their vehicles to honor Busch.
