Farnbacher began competing in the IMSA SportsCar Championship in 2014 with Team Seattle, driving a Porsche 911 GT America.

[8] For the 2022 IMSA SportsCar Championship season, Farnbacher embarked upon a Michelin Endurance Cup-only campaign with Gradient Racing,[9] alongside a full-season effort in the GT World Challenge America with HPD Academy graduate Ashton Harrison.

[11] In GTWC America, Farnbacher and Harrison took four class wins and three further podiums to enter the final race 15 points behind the leaders.

[13][14] Farnbacher began 2023 by taking part in the Michelin Pilot Challenge event at Daytona, driving for HART.

For 2024, Farnbacher left his role as a factory driver for Honda Performance Development to join Aston Martin team The Heart of Racing for the IMSA Endurance Cup rounds.