Jasmine "Jazz" Fenton is Danny's older sister. Viewing herself as the most rational and normal member of the family, Jazz often plays a surrogate parental role to Danny, thinking he is a naive child in need of guidance, unaware that she is often smothering him.
Due to her cherished goal of being a psychologist, Jazz has a bad habit of getting into people's personal space.
When she secretly discovers her brother's secret identity, Jazz has quietly made excuses for him while he went out to fight ghosts, and slowly starts to realize that her brother is growing up fine on his own. Along the way, she learns to appreciate her family's ghost hunting and actively takes part at times.
She has also learned to embrace her sixteen-year-old self instead of acting like an "adult in a teen body".
Jazz estabilished herself as the Society's coordinator and sometime psychiatric for the Society's mentality issue from the first invasion, which most of the member get annoyed or can't even stand to her due to her overly-optimistic personality.
Jazz also one of Society female group led by Atomic Betty, which also act their strategic-experts and legal guardian for her adopted-cousin, Dani Phantom.