She first appeared in the episode "Stupid Girl", whom Malcolm had a crush on. Being dumb like Reese, he managed to calm down and relax to win her over. Alison and Malcolm went to the dance together. While on their way drinking, Stevie and Lois busts them in the act. They broke up right away soon after. However, Reese soon started dating her.
In Malcolm Holds His Tongue, Reese wishes to accompany Alison to a concert, but unfortunately he had his license suspended and had to turn to Craig Feldspar to chauffer them there. Along the way, he has plans for his own night out and intentionally passes the concert. When Reese and Alison complain about it, Craig snaps and tells them that they're not going to the concert because they're on a hayride, dinner and then have a bonfire at the beach they're going to cherish whether they like it or not. Alison fed up with Craig and pepper sprays his face with a can of mace. She is ready to give Reese the same treatment if he doesn't let her go her own way. She gets out of the car and attends the concert alone.
Alison was last seen in "Academic Ocathalon" when Reese refuses to take her to the dance even though he promised her. He finally agrees to take her there, but she soon breaks up with him, possibly out of revenge for trying to get out of his original promise by injuring his foot.
Alison and Reese became boyfriend and girlfriend in the episode Stupid Girl. They both shared the same intelligence level, so when they had conversations with each other, they both totally understood each other. In the episode Academic Octathalon, Reese made a decision that was too stupid even for Alison. The school dance was coming up, and he wanted to ask out Alison, but he didn't want to ask out the person he was already dating. So, he tried to make her break up with him intentionally, so that he could ask her out later. Alison figured out about this plan and forced Reese to give her the perfect prom date, so that she could permanently break up with him afterwards.
Malcolm is the ex-boyfriend of Alison. They used to date in the episode Stupid Girl. Malcolm was way too smart for her, but he still wanted to stay with her, so he shut his brain off and started acting like an idiot, which soon got him involved with drinking, which got him in a lot of trouble. After this, he broke up with her.