Abigail Brown is a deutogonist in The Third Wheel and the main antagonist in Hard Luck. Rowley hooked Greg up with Abigail for the school's Valentine's Day Dance, after hearing that her date, Michael Sampson, had "family obligations".
In The Third Wheel
When Rowley gives Greg the news that Abigail and Michael Sampson split three days before the school dance, Greg immediately takes his chances at going with her to the dance. However, he gets an idea to use Rowley as a wingman, not knowing Abigail.
Rowley and Abigail take a shine to each other on the way to dinner. Greg tries to make sure that she doesn't run off with Rowley by telling her that Rowley wasn't trying to be funny when he asked Abigail if he wanted a sip of a drink he'd been drinking.
In the middle of the dance, Michael Sampson comes in with Cherie Bellanger, and Abigail starts crying because she found that family obligations story was a lie and that Michael broke up with her. After she goes to wash her face, Greg invites her to dance, but Greg freaks out when he sees a pimple on Abigail's face, and thinks that it's chicken pox, this saddened Abigail and ruined any chances Greg had with her.
It is later mentioned by Greg that Abigail does run off with Rowley. This leads Greg to say that Rowley is the worst wingman ever if it was true, thus screwing him over of his date.
In Hard Luck
Abigail is the main antagonist in Hard Luck. She and Rowley are revealed to be a couple in this book. This causes Rowley to start dressing and behaving differently much to the disdain of Greg. They are voted as Cutest Couple in the yearbook and Greg resigns as a yearbook photographer as he has had enough. However, by the end of the book, Greg reveals that Abigail and Michael wound up getting back together after breaking up with Rowley and Cherie Bellanger, respectively.
It's implied that Abigail was never into Rowley in the first place and was only dating him to try and make Michael jealous—even if Rowley was kind of a jerk to him for most of the book, Greg felt bad for Rowley and also felt that the way Abigail broke up with Rowley was kind of harsh. However, after Abigail breaks up with Rowley and gets back together with Michael, Greg and Rowley patch things up and become friends again.
- It is unknown exactly why Michael Sampson cheated on her, maybe it's because Cherie Bellanger and he started to like each other or he was picked to be her date in Valentine.
- Her father is a state trooper, or at least he dresses up like one.
- Abigail is shown to have poor manners when she orders the most expensive item at Corny's and barely touches it at Greg’s expense.
- Abigail has had at least two boyfriends: Michael Sampson and Rowley Jefferson.
- Abigail shows an extreme disliking to Greg throughout her relationship with Rowley, and caused Rowley to change a lot for her own liking.
- Abigail is likely a retired character and has made no further appearences since Hard Luck.
- The reason why she might dislike Greg is because of the incident that occurred during valentines school dance, in the The Third Wheel.
- Abigail is shown to really sensitive, proven in Diary of a Wimpy Kid: The Third Wheel, crying when Michael Sampson arrived at the dance.