On January 27, 2021, it was announced that Dillon would drive for Joe Gibbs Racing in their No. 54 Toyota part-time in the Xfinity Series in 2021, running the season opener at Daytona, Homestead, Las Vegas, and Talladega in the spring. He joined Our Motorsports for the Charlotte race in May. Cup Series Part-time (2014–2016) On July 15, 2014, RCR announced Dillon will make his Sprint Cup Series debut in the No. 33 with Hillman-Circle Sport LLC in partnership with RCR in the Oral-B USA 500 at Atlanta Motor Speedway. After qualifying 29th, he finished 25th. Dillon returned to the No. 33 for the Quicken Loans Race for Heroes 500 at Phoenix International Raceway, qualifying 26th and finishing 27th. In September 2014, sponsor Yuengling and RCR announced they would field the No. 33 for Dillon at the 2015 June Pocono race. On December 9, RCR stated Dillon would drive the No. 33 for Hillman-Circle Sport in the Daytona 500. In 2016, Dillon joined Circle Sport – Leavine Family Racing, splitting the No. 95 with Michael McDowell with sponsorships from Cheerios and Nexteer among others. Like the 33, the 95 has an alliance with RCR. Dillon also ran the No. 14 for Stewart-Haas Racing, substituting for an injured Tony Stewart. Dillon would finish seventh at Talladega for the running of the GEICO 500, but the credit would go to Stewart since he started the race. At Pocono, Dillon would lead his first three laps in Sprint Cup competition. Dillon took over for Regan Smith in the No. 7 Tommy Baldwin Racing Chevy at the Teenage Mutant Ninja Turtles 400 as Smith flew back to North Carolina to await the birth of his child. On November 28, 2016, it was announced that Dillon would replace veteran Casey Mears, who has been with Germain for six years, in the No. 13 GEICO-sponsored Chevrolet for Germain Racing in 2017. Along with GEICO, Twisted Tea was a primary sponsor of Germain Racing for a few races in 2017. Germain Racing (2017–2020) Dillon began the 2017 season with a crash in the Daytona 500. In the next race at Atlanta, he scored a 15th place outing. The next week at Las Vegas, he finished in 21st place. He followed this up with a 16th place finish at Phoenix, a 22nd place finish at Martinsville, and then a 17th place finish at Texas. He followed this finish