Janine is the youngest daughter of a working class family. Though her parents, sister, nephew and grandmother all live in Canarsie (as seen in "Janine's Day Off"), she has remained in Brooklyn Heights, where she grew up. She tends to wear loud, blocky jewelry and (in early seasons) tends to wear a mini-skirt at work.
In 1987, Janine owns a convertible red Volkswagen Beetle, which is severely damaged after being loaned to the Ghostbusters in "Beneath These Streets". In "Baby Spookums" she has a yellow Renault 5 Le Car, although it is not known if this is a loaner/rental or her own car; in later instances she owns a pink Beetle convertible.
She has a sharp, sarcastic sense of humor and has been known to make jokes about the Ghostbusters, either to their faces or under her breath, but most of the time she usually gets along with Ray and Winston, while usually having a kind of sibling rivalry with Peter.