Biffle returned to SST for the 2019 season, sharing a Continental AG-sponsored truck with Sheldon Creed and Ryan Beat.[19] He ran his first races of the year in late July at Mid-Ohio Sports Car Course.[20] In the weekend's first round, he battled with Gavin Harlien for the lead until Harlien began suffering mechanical trouble; on the final restart, Cole Potts passed Biffle to take the race win.[21] The second round saw Biffle pit under caution for damage, but was able to finish fourth.[22] In October, he ran his first SST race in Australia at Surfers Paradise Street Circuit.[23] In practice, he was the fastest in the ten-driver field but did not set a qualifying time after flipping his truck when he hit a tire barrier.[24] He ran in second for much of the first race before falling to fourth after an erratic landing; the second race saw a late spin drop him to eighth.[25][26]