[3][2] Gerwig reportedly earned the name, Killer, when he performed his famous finishing move, the brainbuster, on his opponent by holding him upside down for a period of time and allowing the blood to rush to the brain.

[4] As a singles heel through the sixties, he was a top-of-card fixture battling well-established crowd favorites such as Mark Lewin, Spiros Arion, Tex McKenzie, Dominic DeNucci, and Mario Milano.

On February 21, 1967, he and "Iron" Mike DiBiase defeated Pedro Morales and Ricky Romero to win the Worldwide Wrestling Associates' WWA World Tag Team Championship.

Fans longed to see the brainbuster deployed on the side of good, and this boon was granted in 1971 when the Killer turned into a babyface in a nationally televised mea culpa - he pledged to change his ways on a solemn promise to his dying mother.

This created much heat in the already booming Australian wrestling promotion, where the fixture was an ongoing television "war" between the good guys referred to as the "People's Army" (Lewin, Curtis, Arion, Milano and visiting faces from overseas) and the "mercenary soldiers" managed by Kentucky biker / preacher Big Bad John.

In the wrestling profession, Killer Karl Kox was always a popular figure for his humor, behind-the-scenes practical jokes and inventiveness in furthering the promotion ("the greatest gimmicks man in the business" said one admiring colleague).

At the end of one season, Kox "left Australia for medical treatment in the states" when, in a strap match with Bulldog Brower, his eye was nearly removed (the wound was unbandaged to show the television audience).

A headline making event was when a television match for the IWA World Heavyweight Championship against Spiros Arion was declared ended due to time limit by well-loved commentator Jack Little.