- „It's not about getting it right... It's about knowing when it's wrong and doing something about it”
- —Andie to Pacey[src]
Andie McPhee is introduced as a somewhat high strung, but sweet and intelligent girl, with great academic ambitions and a very sociable nature. She is an enthusiastic and passionate person, and also possesses an innocent nature, although this innocence could also be a stuborn determination to keep some childhood joy in the face of the immense responsibility her parents have left her and Jack with. Her drive can, at times, take on a 'tunnel vision' intensity and she can be a bit ruthless to the people around her. This is more likely due to the extreme pressure she and Jack are under from 1997-2000, after their brother Tim dies and the effect it has on the McPhee family.
After her brother dies and her father moves the family to Capeside, Andie, in spite of great odds, is determined to maintain her academic status and sunny demeanor, refusing to let her mother's condition weigh on her outlook on the world. She has trouble reconciling with Jack's attitude toward their situation, as he faces the seriousness of it head on. Meeting Pacey is a light for Andie, and she soon becomes friends with Joey, Jen and Dawson too. Andie quickly finds herself having feelings for Pacey, though she feels they may be unrequited.
But Pacey starts to feel the same way and they begin a romance, in spite of Andie's wariness with letting Pacey become a part of her increasingly difficult home life. Ever the ambitious student, Andie decides to run for student body president, inspiring Pacey to be her campaign manager and convincing Joey to be her running mate. Abby Morgan's bullying and revealing Andie and Jack's family tragedy to the entire school has a great impact on Andie, as she's becoming more and more unravelled. At the behest of her brother, she begins taking medication again, despite not wanting to.
Feeling better following this episode, Andie and Pacey draw ever closer and Andie begins to consider sex. Even though she's nervous about experiencing her first time, she's also open to and excited about the experience. Her insecurities following such a vulnerable moment get to her when she thinks everyone at the school knows and accuses Pacey of gossiping. This is mostly due to Pacey withdrawing from Andie, but she finds out it's because of how intense and strong his feelings for her are.
Andie's emotional well-being continues to deteriorate as she feels more and more overwhelmed with having to care for her mother and do well in school. She tries to push Pacey away as a result, but he insists on being there for her. Andie spends some time with the other girls where she talks about the difficulties she faces openly. When Jack opens up and starts living his truth, Andie reacts by shunning him at first as she just can't deal with any more public scrutiny, but she comes around thanks to Pacey and supports Jack by throwing out her father when he continues to harass Jack, strengthening their bond as a family.
Andie starts seeing a therapist to help with her illness, and tries a 'night-of-fun' to ease her daily life. She continues to be fragile, with Pacey increasingly worried for her and the sudden death of Abby Morgan triggers a nervous breakdown as Andie begins seeing the spectre of her dead older brother, Tim. Pacey and Jack manage to help her through the breakdown, but Andie is terrified and Jack calls in her father to help, who ultimately decides that Andie and her mother should both receive treatment.
Andie spends the summer in a facility receiving treatment and slowly, but surely gets better. She finds a close friendship with Marc, another patient at the facility, but they sleep together for comfort amidst the hardship Andie's going through. Her return to Capeside prompts her break-up with Pacey when he tells her and, without Pacey, Andie starts to worry whether she will get sick again and wants to ensure her academic future as a way to feel safe. She does this by cheating on the PSATs, with a copy Eve gives Dawson, to secure a great score , and proceeds to make a clean, curt break with Pacey and start dating an older guy.
- Andie was a fan favorite on the series, appearing first in the Season 2 premiere The Kiss, and quickly became a love interest for Pacey Witter.
- The character was brought back for two guest appearances in order to provide closure for her character and to support the ongoing storylines at the time:
- In Season 4, when Andie returned to graduate.
- In Season 6, to say goodbye to Jen and to show where Andie was in 2008.
- Kevin Williamson disliked Andie's departure from the series:
- "I wasn't thrilled with the way Andie left the show because I really loved that character when she first came on. And by the time she left, everyone hated her. I didn't think the audience needed to turn against her the way they did. That's why I wanted to bring her back for the series finale"