Walker was the main antagonist of the live-action film Teenage Mutant Ninja Turtles III - due to the time-travelling plot of the film Walker was one of relatively few TMNT villains who was not active in the modern age but rather during the early fifteenth century.

Walker was a bloodthirsty weapons-dealer who often spoke of his joy for killing, despite this he had an uneasy alliance with Lord Norinaga in Feudal Japan - who he was providing with guns and cannons by which to gain unjust power.

Walker and his men would continue to cause havoc in Feudal Japan until ultimately Walker met his demise in what is known as a "Disney Death" (one in which a villain falls to their seeming death) after trying to escape once his plans had been foiled by the Turtles and a resistance movement opposing both Walker and Norinaga.