Frankie Foster is the pretty, capable, easygoing granddaughter of Madame Foster. Frankie, who has spent her life in the company of Imaginary Friends, takes on the role of taking care of pretty much everything at Foster's. She is in charge of cooking, cleaning the house, doing the laundry, running fund raisers, occasionally working as a handyman, driving the house residents around in the multicolored bus, and otherwise taking care of her grandmother's foster friends in most ways. She occasionally shows signs of stress as a result of her many duties, though its primary source seems to be Herriman's constant over-enforcing of the house rules and that he forever expects her to work harder despite her already full workload. Still, despite all her work, she does manage to keep a social life and is even allowed to go on the occasional date. She is also often swayed by Bloo's "get rich quick schemes" and has proven to be an efficient ally in promoting Bloo's agendas when she feels she can get a good profit or an outcome out of it. She is a fan of punk rock, she also has an unhealthy addiction to Madame Foster's home-baked cookies, occasionally indulging in a feeding frenzy, first buying $1200 worth. In addition, she may have a case of road rage, Frankie also gets extremely stressed out. Frankie is also friends with most of the imaginary friends at Foster's (particularly Wilt, Eduardo, Coco, and Bloo. She can be described as a protective big sister to them. Frankie is also enemies with Mac.