Stewart was penalized for "actions detrimental to stock car racing" and is on probation until Dec. 31. In addition to the fine and probation, the 31-year-old Winston Cup driver also will be required to apologize the Indianapolis Star freelance photographer Gary Mook, who downplayed the incident.
"It is imperative that we protect the integrity of our sport," NASCAR president Mike Helton said. "This type of behavior cannot be tolerated and is in no way indicative of the manner in which our drivers, teams, tracks and sponsors interact with the media. We take pride in our accessibility and interaction with the media and we intend to protect that relationship."
Stewart led 43 laps after starting from the pole and was a contender late in the race at Indianapolis Motor Speedway. But the handling on his Pontiac Grand Prix started to give and his chances to win faded.
The native of Rushville, Ind., finished 12th and was visibly upset.
As Stewart was heading to the team transporter to exit the speedway, Mook took several pictures, which irritated Stewart. According to witnesses, Stewart took several swings at the photographer, including a few that made contact.
Mook did not comment on the incident, but team owner Joe Gibbs talked to the photographer in an attempt to smooth things over and exchanged business cards afterwards.
This marks Stewart's latest temper-related incident. Last year, after being black-flagged late in the Pepsi 400 at Daytona, he slapped a tape recorder from a reporter's hand and kicked it under a transporter.
He also has had a handful of altercations with other drivers, including a highly publicized shoving match with Jeff Gordon.