Throughout her duration on the series, Jenny went on a journey from the very first episode, which portrayed her as a selfish egotist; many observers have perceived her as a narcissist, and even as a borderline sociopath. This latter assessment was based early on around her recurrent lying and the fact she seems to excuse her own cheating in the first few seasons as a corollary of empowerment and as research for her book: which features an experimentalist female character who is evidently herself.
Kirshner has described Jenny as mostly being duplicitous and confused. Jenny often acted "utterly impulsive". Kirshner said it is very hard for people in the series and the viewers to like Jenny because she is "a very despicable character who lies, cheats, behaves and treats other people horribly for no reason, and is extremely selfish, self-indulgent and so terribly truthful... and she does not hesitate to hide any of it."
Showrunner Ilene Chaiken decided to keep audiences guessing about Jenny's sexuality. She stated that whilst sexuality can be fluid, that Jenny's sexuality "definitely exists on the edge of fluidity". This was because she had planned to have Jenny romantically involved mostly with females, but with some males too.