Heintz was a member of the Thule Society, and the driver of Commandant Eckhart in 2013. After Heintz entered the house Aaron Bass was renting in an attempt to secure the Ledger of the Thules, Bass's Golem picked Heintz up, and almost strangled him. The Golem was stopped when Eckhart arrived, and frozen in place when the Commandant used a command in a different language. After Sam and Dean Winchester shot Eckhart's two other men, Heintz used Bass as a shield before running out the door.
With Aaron Bass and the Golem having hunted down and killed half of the Thule between 2013 and 2016, it is unknown whether or not Heintz is still alive.