T.J. is a green Hummer H1 who often attends Sarge's SUV Boot Camp in Radiator Springs. He was introduced as a minor character in Cars, appearing during the epilogue sequence. He later starred in the book Sarge's Boot Camp, which depicts him arriving in Radiator Springs, and half-heartedly enlisting in Sarge's "car camp" alongside Luigi and Guido.
According to the Car Finder Game and subsequent reference material, T.J. is an aspiring rapper from Bloomfield Hills, Michigan, and came to Radiator Springs after his father enrolled him in Sarge's SUV boot camp. While he values his appearance and approaches new situations with caution, Sarge's Boot Camp shows him setting aside these fears, as he befriends Luigi, Guido, and Sarge.