Maddie is the teenage candy-counter girl at the Tipton Hotel, a cashier at the Cluck Bucket, manager of the Camp Tipton Daycare Center, and a counselor for her school's summer camp, Camp Heaven on Earth. In the season 1 episode, "Pilot Your Own Life", her full name was revealed.
While she comes from a lower class family, Maddie is very hard-working, outspoken, and intelligent girl, but in several episodes, she is shown as being selfish and uses London Tipton and her money and power (mostly at the cause of London's own selfishness or stupidity), though she always loses out when this side of her personality is shown. Though she has a firm will and independent mind, she is easily bribed by London into doing or saying almost anything. She is Irish Catholic and attends a Catholic school called "Our Lady of Perpetual Sorrow" (A name taken from the fourth season) and later, attends Cheevers High with Zack, Cody, London, and Nia. London often provokes her, saying that she has ugly hair and clothes and often treats her like a servant, as in the episode Footloser, usually bribing her with money. Maddie also babysits Zack and Cody, and gets along well with their mother, who sees Maddie somewhat like a daughter. Zack has a crush on her in Season One, and all Seasons 2-3 and even shows to still like Maddie in the Suite Life On Deck episode Maddie On Deck . She is a strong supporter of environmental causes. She is left-handed. In the episode Kisses and Basketball it is revealed that she has asthma.
During most of season three, she was gone helping at a summer camp called "Camp Heaven on Earth"; after that, she spent a semester in Antarctica. It was later revealed in Team Tipton that she was in Antarctica saving the penguins. She was absent for a numerous number of episodes and was replaced with Nia Moseby. However, she returned in the episode Team Tipton. She left again after Team Tipton only because of Disney Channel airing the episodes out of order. She returned again in the episode Foiled Again. In Lip Synchin' in the Rain, a recurring joke is made that when she says she looks like Sharpay from High School Musical, High School Musical 2, Sharpay's Fabulous Adventure and High School Musical 3: Senior Year, no one else sees the resemblance (Even though she, Candace and Sharpay are played by the same person). She will not return as a main character on the spin-off, The Suite Life on Deck However, she appeared on The Suite Life on Deck episode "Maddie on Deck" as a guest star, and was mentioned on "Sea Monster Mash". In "Maddie on Deck", she meets Bailey Pickett (played by Debby Ryan), and they quickly become friends until Gabriella Montez and Troy Bolton had a crush in Wipeout Canada (Chocolate Thunder). They go to a castle and the prince sees Maddie and wants her to be his date. But it turns out, he is only 8. Maddie accidentally accepted a gift, letting the prince marry her. The only way was for a peasant (Zack) to battle against the prince. In the end, Maddie kisses Zack and he gains more confidence and beats the prince and won Maddie's heart. Also in "Maddie on Deck", Cody stated that Maddie saved up her babysitting, cashier money, and the money between the cushions, just to buy a bus ticket to the airport, London paid for her plane ticket (coach of course).