Kahne's first win of the season in the Sprint Cup Series came amid several late-race restarts at Infineon Raceway in Sonoma, including a green-white-checkered flag finish in which Kahne nipped Stewart by 0.784 seconds.
Stewart increased his lead in the point standings over Jeff Gordon, who finished eighth.
Marcos Ambrose came in third despite having to start from the back of the pack after blowing an engine in Saturday's practice runs.
Copyright 2009 by United Press International.