In 2018, Miller competed in two WeatherTech Championship events with his former IMSA MICHELIN Pilot Challenge team, CJ Wilson Racing. He won the 2016 Motul Petit Le Mans, which was the same year he ran at the 24 Hours of Le mans. Miller was the 2009 runner-up in the Mazda MX-5 Cup Championship after winning the US Rotax Championship in 2008.