[3] In the 1992 Indianapolis 500, Barnhart was the left-rear tire changer on the pit crew of Unser's winning car.
[4] In 1993, he served as chief mechanic for Al Unser Sr.'s King Racing, Kenny Bernstein-owned entry.
[2] For the 1997 season, Barnhart had been hired by the Indy Racing League (IRL, now IndyCar Series) and was serving as its director of operations.
[2] On March 11, 2007, prominent open-wheel journalist Robin Miller reported that the IRL was seeking a new leader for its marketing side and that once found, Barnhart would return to his operations role.
[citation needed] During the 2011 season, Barnhart was criticized by fans, drivers, and owners, and especially Miller for inconsistencies in his role as chief race steward.
[13][2] For 2023, Barnhart joined Arrow McLaren, being named general manager after president Taylor Kiel left the team.