Ron Silver almost turned the project down because he was busy with Veronica's Closet (1997). But he liked the script so much he made time in his schedule.
This pilot was written for the ABC network which passed on it. NBC and Fox had a bidding war over it which Fox won.
The short is actually a parody of Northstar, a 1986 failed pilot turned TV movie about an astronaut called Northstar who gets irradiated by the Sun during a NASA mission, which somehow significantly enhances all of his senses but also makes him allergic to bright Sun. Heat Vision and Jack also spoofs more popular shows like Night Rider, a show about a talking car and his driver who stop crime, and less directly Dr. Who, a long running British show about an omnipotent benevolent alien who calls himself doctor Who and helps humanity against various alien and other threats. The most popular villain on Dr. Who is a race of xenophobic alien artificial life forms or robots called Daleks who have only one goal in mind - to eradicate all humanity. This is also the plan of the villainous artificial life form in Heat Vision and Jack. As an in-joke, Heat Vision watches one of Dr. Who episodes on the TV in the sheriff's grandma's house. The episode features the Daleks as well as their creator Davros being defeated by the Doctor.
Judy Greer auditioned for the role that eventually went to Christine Taylor.