During the glory days of the World of the Future Fair, Hazel was located at the House of the Future attraction, where viewers could see her cutting food on the kitchen table with a knife while their carts passed by, like when Andrea Beaumont and Bruce Wayne visited the park during one of their dates.
Some time after the park became derelict, the Joker used it as his hideout. Surprisingly, Hazel continued to function after all of those years, though she had begun to deteriorate, mainly because the Joker took off part of her attire sometimes. She was present during Salvatore Valestra’s brief visit to the House of the Future. One night in particular, the Joker gave Hazel a giant sausage to slice, but the Phantasm, who revealed itself to be Andrea Beaumont in disguise, arrived to kill the Joker and avenge the death of her beloved father. After a brief scuffle, the Joker activated Hazel with a button on the kitchen table, causing her to abandon her position and attack Beaumont with the knife while giggling maniacally, but Beaumont dispatched the robot via kicking it to the floor. However, this gave the Joker time to leave the attraction quickly to detonate the complex. By activating the bomb in the House of the Future's oven, the controls caused Hazel to give one last laugh before the attraction, and subsequently the entire fair exploded, taking Hazel with it.
Writer Paul Dini commented that Alan Burnett created the character of Hazel after Hazel the Maid, The Saturday Evening Post main character of cartoonist Ted Key's TV show Hazel, portrayed by actress Shirley Booth. In turn, Dini thought that the Hazel character was created as a nod to Rosie, the household robot of The Jetsons.