Colonel Heller was an ex-Green Beret and the head of security for South American drug lord Franz Sanchez. CIA agent Pam Bouvier attempted to make a deal with Heller which would allow him to return to the United States, but he was scared away from the agreement by the interference of James Bond in Sanchez's operations. When Sanchez subsequently became suspicious of Heller, he had him killed by Perez.
Heller was Sanchez's trusted head of security until one night CIA informant Pam Bouvier visits him at the Casino de Isthmus in Isthmus City. She brought with her a letter promising Heller exoneration for his previous crimes, allowing him to return to the United States in return for bringing with him Sanchez's stinger missiles, themselves acquired from the Contras by Dario. However, Heller was scared off of the deal due to James Bond's assassination attempt on Sanchez.
After Bond's capture by Kwang, Loti and the ninja, Heller pursued them to Kwang's safehouse and shelled the building with his tank. Kwang, the ninja and MI6 agent Fallon where he killed in the assault. Loti survived and managed to kill two of Heller's men, before Heller gunned her down with his sidearm.
When Bond later destroyed Sanchez's drug lab at the Olympatec Meditation Institute, Heller decided to try and make a run for it with the stingers during the chaos. However, he was caught by Sanchez, who ordered Perez to kill Heller. Perez obliged, impaling Heller on the pellet holder of a forklift which subsequently crashed through a wall.