The Milkman is first seen driving his truck until he is scared half to death by O'Malley, who manages to jump in front of his truck front window from a tree, screeching, thus forcing him to drive somewhat out of control as O'Malley disappears out of sight and then stop his truck to try and fix it while insulting O'Malley.
As the Milkman is able to start up his truck again, O'Malley, Duchess and her kittens: Berlioz, Toulouse, and Marie manage to sneak into the truck and use it as a ride back home to Paris. Later, after O'Malley offers the kittens some milk for them to drink, the Milkman unfortunately finally notices them on his rearview mirror, thus forcing to stop his truck yet again only a little more violent this time. As the truck comes to a stop, O'Malley accidentally "flies" towards the Milkman and ends up on his head. The Milkman tries to grab him but misses as he and the other cats try to escape him. As the cats are running away scared from him, the Milkman chases them away with a wrench and a bucket, which he throws at them but misses while insulting them and then continues driving his way. The Milkman isn't seen throughout the rest of the movie after this.