It was the 100th Nationwide series victory for team owner Jack Roush.
Biffle led the final 106 laps, many of them with Kevin Harvick on his bumper. A caution came out with 20 laps to go and both Biffle and Leffler stayed on the track while the rest of the leaders came into the pits for fresh tires.
Biffle pulled away from Leffler on the final restart to win his second Nationwide race of the season and the 20th of his careers.
Brad Keselowski finished third, followed by Joey Logano and Harvick.