Born in 1958, Stefanik built his career primarily in the Northeast short-track racing scene. He became known for his consistency and versatility, competing effectively across multiple NASCAR touring series throughout his career. His nine total championships across the Modified and Busch North series tied him with Richie Evans for the most championships in NASCAR history. In 2003, he was named the second greatest NASCAR Modified driver of all time.
Stefanik ran his first full Whelen Modified Tour season in 1987 and claimed his first championship in 1989, winning seven of his 26 starts that year. He continued to be a dominant force through the 1990s, adding the 1991 series title and then pairing Whelen Modified Tour championships with simultaneous Busch North Series titles in 1997 and 1998. That double-championship feat in consecutive years was unprecedented in NASCAR — Lee Petty is the only other driver to have won two NASCAR championships in one year, though under different circumstances.
In 2000, Stefanik stepped away from Modifieds to run full-time in the Camping World Truck Series, where he earned Rookie of the Year honors in 1999 after nine top-ten finishes for Phelon Motorsports. When he returned to the Whelen Modified Tour he won back-to-back championships in 2001 and 2002, relying on consistent top-ten finishes rather than outright race wins. After a period focused on the K&N Pro Series East, where he had previously won the 1997 and 1998 championships, Stefanik returned to dominate the 2006 Modified season, completing every lap in the series across the entire year and leading the standings for all but one week.
In the K&N Pro Series East, Stefanik also made his mark. He won in only his third start in 1991 and claimed back-to-back titles in 1997 and 1998, pocketing over $100,000 in each of those championship seasons. His success in winning championships simultaneously in multiple series in consecutive years was a feat without precedent in NASCAR.
Stefanik's pace slowed in his later seasons. His first full winless season in the Whelen Modified Tour came in 2010, and he won his last race in the series at Bristol Motor Speedway in 2013. His final series start came in 2014.
A memorable moment from his twilight years came at the 2013 UNOH Battle at the Beach at Daytona International Speedway, the inaugural running of that event. Stefanik was leading on the final lap when contact from Steve Park sent him spinning; he ultimately finished 13th. His candid and colorful post-race remarks to a Speed Channel reporter were subsequently aired nationally on The Jay Leno Show.
Stefanik's nine NASCAR championships — seven in the Whelen Modified Tour and two in the Busch North Series — tied the all-time record held by Richie Evans. He was elected to the New England Auto Racers Hall of Fame in his first year of eligibility, inducted on November 11, 2018. He was first nominated for the NASCAR Hall of Fame in 2015 and was ultimately elected, joining the class of 2022 (announced as part of the 2021 class).
On September 15, 2019, Stefanik died following a light aircraft crash in Connecticut. He took off in a friend's Aero-Works Aerolite 103 ultralight from Riconn Airport in Greene, Rhode Island. The aircraft experienced mechanical problems, lost power, and crashed in a wooded area in Sterling, Connecticut. Stefanik was airlifted to Rhode Island Hospital, where he succumbed to his injuries. He was 61 years old.
His career stands as one of the most successful in NASCAR Modified history, built on durability, versatility, and an ability to compete at the championship level across multiple series simultaneously.