Trivia

Had to undergo some dental work during the filming of Freddy vs. Jason (2003), but it would have taken too much time to remove his makeup and costume and reapply them. When he arrived at the dentist's office still dressed as Jason (without the hockey mask), people were afraid he was an escaped psychopath and almost called the police.

According to Kirzinger, the hardest thing he went through for performing as Jason in Freddy vs. Jason (2003), was sinking into the lake. They shot the scene in a tank which was highly chlorinated and had debris to make it look like lake water. Director Ronny Yu wanted the close-up of Ken's eye and wanted him to sink into the water keeping his eye open. Then also he can't breathe because it would be visible on film. He was lying on top of the water and had to let himself sink down to the bottom of the tank without breathing keeping his eye open. Kirzinger really held his breath, and the chlorine in the water burned his eyes.

At 6'5" he is the the second tallest out of the nine actors to have played Jason Voorhees. Height wise, he's tied with Derek Mears who played Jason Voorhees in Friday The 13th (2009). Derek Mears is also 6'5".

Long before he took over the role of Jason Voorhees from Kane Hodder, Kirzinger appeared in Friday the 13th Part VIII: Jason Takes Manhattan (1989) as a New York cook who gets in Jason's way when he is pursuing Rennie Wickham (Jensen Daggett) and Sean Robertson (Scott Reeves), and Jason (played by Kane Hodder) threw the bigger Kirzinger over the counter.

While filming the scene in the fiery cabin where Freddy Krueger and Jason Voorhees confront each other in Freddy vs. Jason (2003), Kirzinger actually caught on fire. Being a stuntman for twenty-four years at that time, he remained calm while stage hands rushed in with fire extinguishers to put the fire out. This incident is discussed in the DVD commentary for the film.

In his first interview concerning Freddy vs. Jason (2003), he did the whole video interview in Jason's costume wearing the mask, clothes and make-up, in order to make the viewers more confident in him and his loyalty to the character.

Is good friends with Brad Loree, who portrayed Michael Myers in Halloween: Resurrection (2002).

Was one of the stunt coordinators for Friday the 13th Part VIII: Jason Takes Manhattan (1989).

He made guest appearances on all three of the longest running North American science fiction series: The X-Files (1993), Stargate SG-1 (1997) and Smallville (2001).

Director Ronny Yu and the producers of Freddy vs. Jason (2003) tried to limit his doing his own stunts as much as possible.

Brother is Dave Kirzinger, who was playing for the Calgary Stampeders (CFL) from 1978 to 1986.

Born on exactly the same date as Deborah Rennard (of "Lionheart", "Dallas", and "Gang Related" fame).