Jenny is a young 8-year old girl. She wears an iconic frog hood, a yellow shirt with pink buttons and a pink flowery skirt, socks with a strawberry imprint on them at the knee that cover most of her lower legs, and red dress shoes. Her reddish-brown hair has two little buns and straight-cut bangs, though most of it isn't seen unless she takes off her hat.
Jenny Is a fun-loving girl that enjoys drawing and coloring, which she is usually seen doing in the living room of the house. She is very friendly and enjoys Chibi-Robo's company, always saying hello to him and giving him a kiss if he brings her any Frog Rings. She also asks for his help throughout the game, as she is at odds with her family due to her "frog curse" and doesn't communicate well with them. The sound she makes is the Japanese onomatopoeia of a frog's croak: "gero, gero".
Before the beginning of the game, Jenny was apparently "cursed" by the "Frog Wizard", which is why she wears a frog hood and speaks in croaks to everyone except Chibi-Robo. If Chibi-Robo brings her all the Frog Rings, Jenny will take her hood off and speak normally, thanking Chibi-Robo for lifting the curse. However, once Chibi-Robo leaves the room, she immediately puts the hood back on and claims to be cursed once more. Jenny appears to be "learning" how to speak her native language again since she forgot how when the "Frog Wizard" cursed her to become a frog. During certain important cutscenes, she is shown to be able to speak more normally than she lets on.
She may be a fairly messy and rambunctious child, as there are large amounts of trash and crayon scribbles found within her room.
Chibi-Robo! Plug Into Adventure!
Jenny first appears in the game's opening, where the entire family is celebrating her 8th birthday. She seems to be unable to speak aside from croaking like a frog, and expresses distaste for the hat her mother gifts her as she's already wearing a frog hood. The family dog, Tao, gives her a bone that she seems to like, and her father then reveals his gift to her is a Chibi-Robo and activates the new device for her. Excited to see the robot in action, she eagerly accepts Chibi-Robo's impromptu gift of a rose.
For the majority of the game, Jenny can be found coloring in the living room during the day. At night, she is in different areas depending on how far the story has progressed.
First, Jenny appears crying in the Foyer after her parents have a fight. When Chibi-Robo finds her, her mother comes in the room and orders her upstairs and into bed. Once Mrs. Sanderson goes on her strike, Jenny is found within her room at night. After the game is completed, Jenny will always be sleeping in her room at night, and during the day she will alternate between coloring in the living room and sitting with her family in the Kitchen. During her mother's strike, she acts more or less the same as she did before and continues her daily routines.
After Chibi-Robo builds a Ladder Utilibot in the Foyer, he is able to visit Jenny's Room. Once Mrs. Sanderson goes on her strike, Jenny will be found staring into her flickering TV screen and mumbling, hinting to the existence of the Aliens. After this first nightly visit, Jenny will be sleeping in her bed at night. When the Spydorz attack the family, Jenny is rushed into the living room and helps the family barricade themselves inside. After the Spydorz are defeated and the family reunites, Jenny is shown to be spending more time with her parents, though she never truly recovers from her "frog curse".
Okaeri! Chibi-Robo! Happy Richie Ōsōji!
Many years after Chibi-Robo! Plug Into Adventure!, an adult Jenny Sanderson dated a man named Karl, and together had a child named Keith. Before the couple could get married, Karl passed away in an unknown accident. Seven years later, she helped purchase a Chibi-Robo in the first family Savings Tournament to try to relive her childhood days owning a Chibi-Robo.
During the Fifth Family Meeting, Keith wishes to have his father back. After this, Jenny locks herself in her room at night. Chibi-Robo and Telly sneak in through the drain, and Jenny tells them about Karl's death.
While Chibi-Robo is searching for the wedding rings that were to be used in Jenny's wedding, she stumbles upon one of them in a box kept in her storage closet. At the end of the game, Chibi-Robo and Telly wake Jenny up and surprise her with the Wedding Dress. She is reunited with Karl's spirit and they get married under the moonlight. After the ceremony, Karl is at peace and his spirit ascends. Keith tells her that she should introduce the family to the coworker who asked her on a date, since Karl would want Jenny to be happy.
After the wedding, speaking to Jenny will get her to tell Chibi-Robo about how she purchased him to relive her childhood, and that Chibi-Robo is a real member of the family.
- Jenny is the only Sanderson to appear in more than one game, although her father is mentioned in Okaeri! Chibi-Robo! Happy Richie Ōsōji!.
- Despite loving frogs, her room has a Sunshine theme instead of a frog theme. This may be due to the fact that Sunshine is her favorite toy.
- It seems like Jenny will not speak as normally around her mom, because if Chibi-Robo has his frog suit on while talking to Jenny, Mrs. Sanderson will notice Jenny talking normally, so this could mean Jenny acts like a frog for attention.