Most of Jenny's present life remains obscure and she has rarely been seen over the course of the summer. What is known is that she lives with her brother Django and is the elder of two children of Beppo Brown.
She first took an interest in Phineas and Ferb's activities when they built an artificial beach in their backyard and came over to spend the day there with Stacy("Lawn Gnome Beach Party of Terror"). She appears to own and care for a dog with a resemblance to a Komondor. It is likely hers judging by a patch of fur resembling the daisy in her hair ("Misperceived Monotreme").
She played a role in the events of the second dimension Doofenshmirtz's invasion when she took control of the Candace Crusher to assist in defense against the attack (Phineas and Ferb The Movie: Across the 2nd Dimension).
She appears to be somewhat of a hippie, based on her clothing and the Peace symbol she wears, along with her hope and desire for world peace ("Day of the Living Gelatin"). Jenny says she doesn't like persimmon ("Phineas and Ferb-Busters!"). She likes pigeons and likes the idea of being Candace's best friend ("The Lemonade Stand").
Jenny has long brown hair decorated by a white daisy. Her usual clothing consists of a yellow turtleneck sweater, a red skirt decorated with wavy orange lines, yellow socks, sandals with orange straps and an orange Peace Sign necklace.