*Penny is Inspector Gadget's niece and one of the main protagonists of the franchise. Penny secretly helps out her Uncle Gadget with his missions and does all the work, but she lets him get all the credit in the end.

In this series, Penny is twelve years old and is the creator of Fidget and Digit, the titular Gadgetinis after Brain was retired from active duty. She builds them other gadgets and features to help them when they go on Gadget's missions. She now uses a laptop instead of a computer book.

Penny is precocious, intelligent, brave, cute, tomboyish, resourceful, and anonymously solves the cases for her Uncle Gadget, something which he is totally oblivious to. Penny also loves her uncle very much and looks up to him. While it is not stated if she and/or Gadget have any other family members in the TV series, movies, or spin-offs, Gadget seems to be the only family she has got, and "Gadget and Old Lace" and a few episodes of Gadget and the Gadgetinis, including "No Brainer", confirm her to be an orphan. Penny foils Dr. Claw's plans, leaving Gadget to get all of the credit for doing so, even though he didn't do anything at all. This makes sense because Penny would be in serious danger if she got the credit.

Penny often stares around M.A.D.'s hideout or setup location to find out what they are up to; however, she usually ends up getting caught by Claw's henchmen and she either escapes by herself or calls her loyal pet dog Brain to rescue her. But when she and Brain are both captured, Gadget becomes exceptionally useful and competent and goes out to rescue both of them. Gadget loves Penny more than anything and he sees acting like a pretty girl. Penny is also very knowledgeable; for example, in "Clear Case", when she and Brain are in a laboratory of a diamond mine in South Africa, she knows how M.A.D agents are making invisibility suits to scare off miners by making them think they are ghosts. Quoting: "Diamonds refract light. They discovered a way to grind them into a powder and make a diamond cloth. It's like a coat made of mirrors: It deflects light so you can't see it."

Penny is also very patient and progressive, particularly when putting up with her uncle's clumsiness and stupidity.

Penny has shoulder-length blonde hair styled in pigtails. In Gadget and the Gadgetinis and Inspector Gadget's Last Case, her eyes are violet-blue. Two years later, she is 12 years old in Gadget and the Gadgetinis and Inspector Gadget's Last Case.

In The Gadgetinis, Penny wears a pink crop top, a green turtleneck, khaki cargo pants, brown belt with silver buckle, and red sneakers. Her pigtails are also straight up. Like the original series, she wears a red bikini at the beach.*