Bonnie Kleinschmidt (spelled as Kleinschmitt in the credits of her first episode) is the girlfriend of Reuben Kincaid.
In They Shoot Managers, Don't They? Shirley Partridge says that Reuben needs a wife. Danny Partridge tries to matchmake. His older friends tell him Bonnie is hot, so he tells her Reuben can get her into show business. Bonnie tracks Reuben down, yanks him out of his car, and starts kissing him. She spends the rest of the morning harassing him.
In This Is My Song, which is apparently set later than They Shoot Managers, Don't They?, Reuben has given in to Bonnie's advances. Danny calls him for help in the middle of a date with her. Reuben tells Bonnie he's going to slip into something more comfortable, then sneaks out of his apartment and goes to the Partridges' house.
In Guess Who's Coming to Drive, Shirley asks Reuben to dinner, but he says he's having dinner at Bonnie Kleinschmidt's house.
In Home Is Where the Heart Was, Bonnie makes her first in-person appearance. After Chris and Tracy Partridge run away to Reuben's apartment, Bonnie shows up, wearing her short-skirted stewardess uniform. She says that she changed flights with another stewardess and will be in San Pueblo for only one night. When she realizes that Reuben has kids in his apartment, she leaves. Reuben gets her to agree to come back in an hour, after the kids are gone.
In A Likely Candidate, Reuben fails to return Shirley's calls for two days because he's advising Bonnie's brother, who has started a club in the mountains. He doesn't return to San Pueblo until Danny pretends he broke his leg.
In Bedknobs and Drumsticks, Reuben is in the middle of a romantic date with Bonnie when the Partridges call, wanting him to come to their house so they can show him the chicken suits. Bonnie asks him to pick up a pepperoni pizza on the way. By the time Reuben gets back to his apartment, Bonnie has gone to work, but has sent Gwen and Frank to keep him company.
As of Season 3, Reuben and Bonnie aren't exclusive. In Swiss Family Partridge, Reuben complains about missing a date with Lola, and in Bedknobs and Drumsticks, Reuben looks forward to a romantic evening with Gwen before he finds out she's married.
In Reuben Kincaid Lives, Bonnie has to cancel a date with Reuben because of work. However, she does get him to say he loves her over the phone, which makes the Partridge kids clap. Later in the episode, she comes to San Pueblo for Reuben's birthday party, in her first appearance out of uniform. Clara Kincaid interrogates her about her and Reuben's plans for the future. At the end of the episode, Clara changes her flight plans so she can fly home on the same plane as Bonnie and interrogate her some more.
In Double Trouble, Keith Partridge interrupts a romantic evening between Reuben and Bonnie so he can ask Reuben for romantic advice. Reuben suggests that he drop the "nice" Sally Winkler and date the "knockout" Johanna Houser. Bonnie is offended and thinks Reuben is implying that she either isn't nice or isn't attractive. She storms out of the apartment.