Flute Girl has long brown hair, glasses with magenta rims, and braces on her top teeth which give her a lisp. She wears a long sleeve white shirt underneath a green sweater vest with a black eight note on the front. In addition, she wears a dark red violet skirt, white socks, and black dress shoes.
When she's involved with the marching band, she'll wear the normal band uniform. Her instrument is a flute that she calls Princess Tootie.
Her normal appearance when she is stanked by the Sorcerer is a blue tyrannosaurus-like monster with a large mouth. In "Lucius O'Thunderpunch", she tries to chomp the Ninja, but he stops her by breaking free and knocking her out. She also can use her tail to grab things, like snatching Rachel in "True Bromance".
Flute Girl does well in school, and gets easily annoyed with anyone who slacks off or comes off as an idiot, especially Randy and Howard. For example, in "McFists of Fury", she couldn't believe they didn't know who Brawn Brickwall was. She also is frustrated with people who don't listen to her, like Bucky doing a triangle "solo" during "Got Stank" and singing instead of buying her a McFist Tunes gift card that she wanted in "Silent Punch, Deadly Punch". She usually follows the rules whether she likes it or not, having no choice but follow Howard to Mt. Chuck because of the five-foot rule. However, she is nice, comforting Bucky about being tricked to go up the volcano in "Monster Dump", and often thanking the Ninja whenever he saves her. She gets easily attracted to guys, like Pitch Kickham, Nightfire, and especially Stevens.
Flute Girl has a major crush on Stevens. In "Randy Cunningham and the Sorcerer's Key", she's delighted when Stevens gives her a band pin. However, she's crushed when she discovers Stevens has been giving band pins to many girls. After becoming stank-fused with Stevens and getting destanked, she gives Stevens his band pin back. By "Julian's Birthday Surprise", though, Flute Girl and Stevens seem to have made up as they're hanging out at Julian's birthday by getting pictures taken at the photobooth and sitting together to watch Nightfire's show. Flute Girl longs to be his girl, and she gets easily jealous whenever Stevens gives other girls attention over her. This is what gets her stanked twice in "True Bromance", the first time because Steven gave Rachel a trombone lesson.