Tony Stewart has been known as the "bad boy" of NASCAR throughout his career, but there are a few facts about the driver that may be surprising. Here are five interesting tidbits about Stewart you might not have known:

Five Post-Race Fights Involving Tony Stewart

Stewart earned the nickname "Smoke," according to CNN, early in his career, supposedly because that's what other drivers saw coming from his tires as he would drive aggressively around the racetrack.

Stewart got an early start behind the wheel, winning his first competitive race in 1979 at the age of eight. No, he wasn't tearing up any NASCAR racetracks, but rather dominating competitive go-kart races. In 1980 he won his first championship in go-kart.

In 1995, Stewart became the first driver the Midget championship, the Sprint championship and the Silver Crown championship in the same season.

Stewart established the Tony Stewart Foundation in 2004. The foundation focuses on caring for at-risk or endangered animals, critically or chronically ill children, and drivers injured in motor racing.

After establishing Stewart-Haas racing in 2009 with Gene Haas, Stewart became the first driver/owner to win the Sprint Cup championship when he won his third Sprint Cup title in 2011. Stewart won that title on a tiebreaker as he had five regular-season wins to Carl Edwards' one.

Stewart was involved in a post-race skirmish last weekend at Charlotte Motor Speedway, but he was hardly responsible for what happened. Brad Keselowski attempted to spin Denny Hamlin after the race in response to an earlier incident, but Hamlin ended up taking out Matt Kenseth. Stewart happened to get involved in the antics and then retaliated by backing his Chevy into Keselowski's car in retaliation for starting the whole thing. Kenseth then approached Keselowski in the garage and put him in a headlock before the two were separated.

Keselowski was fined $50,000 and Stewart was fined $25,000 while Kenseth escaped any penalty.