Before meeting Max, Chumbucket was a blackfinger, a term used to describe those who have an innate understanding of how engines and other mechanical devices work similar to the term grease monkey in the United States. He was working with other mechanics in the engine bays in Gastown, repairing all of the war vehicles for parties that go out and scout the Wasteland for resources. After having a dream he became religiously obsessed with building his Magnum Opus - the fastest, most powerful car in The Wasteland.
He started pilfering from the engine bays, hiding items for his vehicle in his little bunk. His obsession has caused him plenty of trouble. One day he was found out and would have been killed if it weren't for his executioners that wanted to toy with him beforehand. He took advantage of the situation and escaped Gas Town. Chumbucket has since been living in the Wasteland as a wandering artisan of sorts. Being an extremely skilled mechanic, he has built a reputation for himself having made contacts with the nearby chieftains known as Jeet and Gutgash. Even though he’s a bit of a bizarre hermit, people will need him every now and then, so they don’t kill him. He owns a makeshift garage inside of an abandoned ship in a region known as The Outer graves.
In the events of Mad Max, Chumbucket witnessed Max from afar during a road war with Scabrous Scrotus. After the fierce fight, Max's car had been stolen and he was left for dead. Chumbucket, in his religious obsession, immediately concluded that his prayers to 'The Angel of Combustion' have been answered and he's been sent a "Saint", a sacred warrior that will help him in building the ultimate machine of the Wastelands - the Magnum Opus. Thus he helped Max and an unlikely alliance was born.
SPOILER ALERT: He possessed an undying loyalty towards the Magnum Opus. After Max rammed the Land Mover off the road to a cliff. However it kept its own balance on the cliff, and Max plans to fully destroy the Land Mover by giving it one last ram but the Magnum Opus was immensely damaged during it's fight with The Land Mover. Chumbucket tells Max that he can fix it however Max advises to get off the Magnum Opus. Chumbucket realises what Max is going to do and due to his loyalty and time spent building the Magnum Opus, Chum sits on the hood and tries to persuade Max to not destroy the Magnum Opus. However Max drove it into the Land Mover and bailed anyway, Chumbucket remained on the hood thus resulting in his death. His corpse was burned by the Fuel leaking out of the Land Mover then The Magnum Opus explodes and falls off the cliff along with the Land Mover, destroying Chumbucket's corpse.