Mia first expressed an interest in Peter when they connected at his party due to their mutual feelings of rejection, as Darcy Edwards had left Peter to build a school in Kenya, and Danny Van Zandt broke up with Mia after she hooked up with Tom Blake. The two formed a relationship on the rebound, which lasted for a short period of time, until Mia found out that Peter was still in contact and had feelings for Darcy. He, however, convinced her that he loved her, and the two reconciled their relationship. After Peter formed a temporary addiction to meth, Mia broke it off with him, and moved to France for a modeling job. It is shown they had no harsh feelings for one another after their break up, as Peter was able to move on and Mia still talked to him occasionally via webcam. Their first relationship began in Man With Two Hearts and ended in Heart of Glass. They got back together in Danger Zone, but broke up again in Just Can't Get Enough.
Season 8In Fight the Power, Darcy moves to Kenya and tells Peter the day before she goes. He's upset and can't stand to see her go, but when he meets Mia at his back-to-school party, they bond over mutual feelings of rejection. Mia later finds out that Peter is not over Darcy and thinks she is just a rebound. They have lunch together and Clare delivers a gift from Darcy. To make Mia think that Peter is all hers, he throws the gift in the garbage. However, after Mia leaves, Peter pulls it out of the garbage and keeps it.
In Man With Two Hearts, Mia's pressuring Peter to fully commit himself into a relationship that he's not sure he's ready for yet. Later in the episode, Peter then decides to become official with Mia and is freaked out by Riley kissing him. Mia tells Peter that he shouldn't stop being friends with Riley just because he's gay, so Peter decides to talk to him.
In Money for Nothing, Mia reveals to Peter that Entertainment Scoop is doing a piece on her, and he tells her can't think of anyone more deserving of the attention. Later, Mia and Peter are hanging out at his loft, and they begin to slow dance upon Mia's request. They begin kissing, but stop when his mom arrives for a visit. Peter and Mia watch the story about Mia air together, which upsets her. Mia confesses that part of what Holly J. said was true, but Peter says that it is in the past and doesn't matter now.
In Lost in Love (2), Peter and Mia attend the dance together.
In Bad Medicine, Peter and Mia celebrate Degrassi's win at the football game. Later while Anya and Riley are on their date, Anya calls Peter and Mia over to sit with them, and Mia asks Peter to get her what she usually gets while she goes to the bathroom. Later before class, Peter, Mia, and Anya are talking and laughing together.In Heat of the Moment, while Mia is hanging out with Peter (and Angel, his half-sister), Mia tells him that he looks cute with her. When Peter makes a comment that he shouldn't be taking care of his sister's responsibilities, Mia takes offense to his comment. Peter then apologizes as he only made the comment because he is actually jealous, because his father never paid a lot of attention to him. Mia advises him to confront his dad and Peter leaves with Angel to do just that. She is then seen with Peter and Angel at school.
In Jane Says (1), Anya, Mia, Sav, Peter, Leia Chang and Danny Van Zandt all have a sleepover together. Peter and Mia sit next to each other during the game of Truth or Dare. Everyone gets along well, except Leia is a lot more stiff around Danny's friends. Leia drags everyone down to the Fall Out Boy concert the next day, which they don't have tickets to, and when Leia can't get them in because she lied, Peter and Mia look annoyed. They head back to his loft to watch Lost with Anya and Sav.
In Jane Says (2), Peter and Mia are at The Dot together. Peter notices Clare and the fact she is wearing Darcy's clothes.
In Heart of Glass, Peter tries to get Mia to join the Mock UN, which he is a part of, but she tells him the time conflicts with Power Squad. Anya points out the fact that Peter is representing Kenya, where his ex-girlfriend now lives. Mia later asks him why he chose Kenya, and Peter reveals that he is still in contact with Darcy. Peter avoids the question when Mia asks if it should bother her that he is talking to her. Mia ends up looking through Peter's items, and finds a note from Darcy and an application to go to Kenya for relief work, which makes her unhappy. Anya signs her and Mia up for the Mock UN to make Peter love her more for loving the world. Mia confronts Peter about the Kenya situation, leaving him speechless and causes her to storm out. Peter later confesses he has been thinking a lot about Darcy lately and has been feeling confused since he has feelings for both Mia and Darcy. Mia breaks up with Peter since she wasn't willing to be his "consolation prize" compared to Darcy.
In Up Where We Belong, Peter chases after Mia after she dropped out of school and tells her she is making a big mistake. Peter claims she is giving up and asks if she's leaving because of what happened with them, which causes her to tell him to get over himself.In Danger Zone, Peter keeps trying to win Mia back, but she refuses to give in and tells him that she is always going to wonder what would have happened if Darcy never left for Kenya. Later on in the episode Peter and Sav are playing video games at Peter's place and Sav gets a phone call from his younger sister Alli. He just found out that there were cop cars at The Dot, and that's where Anya and Mia were going after shopping. When Anya and Mia show up to The Dot, Sav runs to hug Anya and he's thankful she is alright. Peter hugs Mia and says he glad she was okay and kisses her. Mia looks puzzled, and Peter confesses his love for her, and said he thought he would never see her again and she would never know how he felt about her. He confesses that he loves her. She then smiles and kisses him back. As a result, they got back together and enjoyed their night together at the Black and White dance.
In Degrassi Goes Hollywood, Peter and Mia head to Hollywood with Danny, Jay, Manny, and Sav.
Season 9In the season premiere, Just Can’t Get Enough (1), Mia is happy to be back from LA with her boyfriend Peter and a whole new load of popularity under her belt. After meeting two new rich kids, Declan and Fiona, Mia and Peter are invited to their party. After they arrive, Mia tells Peter the big news, that she got a job of being a "Euro Fresh Face". She says she is going to take the job and move to France, and after preschool, Isabella Jones and her mom will move there with her. Peter seems happy and decides to go with her. But, when Peter sees Mia's sophisticated ways at the party, he resorts to crystal meth, and decides not to go with her. She notices the meth and tells him to stop. He tells her that everything is all about her and that he's not going with her, signifying that they broke up. Mia leaves for Paris, but tries to tell Peter to stop, even though he doesn't. Later in the episode Mia is seen video chatting with Peter and his mom before a photo shoot. Mia is happy that Peter is clean.
In Pirates of the Cafeteribbean, Jane warns Mia that she told Spinner that Peter made fun of her booty yesterday, and that Spinner might do something stupid in retaliation, advising Mia to warn Peter. Peter approaches them, and asks what he should be warned about. At that moment, Spinner breaks into the cafeteria in search of Peter, and tells Jay Hogart and Craig Manning that they'll get a chest of gold if they bring him Peter's head. Mia turns to glare at Jane, and she apologizes for not being great at "pirate's code". Peter and Mia manage to take control of the ship, and manage to turn it sideways, throwing everyone to the ground.
In If Jay Can't Be Happy..., Peter and Mia are happily sitting together at The Dot, and when their date isn't ruined by Jay's magic, it confuses Jay, Spinner, Holly J., and Sav.
In Good Times, Bruce mentions that Peter has been with Mia, along with Emma and Darcy.
- Mia is the second of Peter's girlfriends to move to a different country. The first was Darcy Edwards.
- Peter kissed Mia's good friends Chantay Black and Jane Vaughn but only as part of a play in both instances.
- Mia briefly dated Peter's good friend Danny Van Zandt.
- Mia kissed Peter's good friend Sav Bhandari.
- Mia had a conflict with Darcy Edwards, Peter's ex-girlfriend.
- Peter had a conflict with Mia's good friend Manny Santos.
- Peter disliked Mia's former friend Leia Chang.
- Their first on-screen kiss was in Man With Two Hearts.
- They are the second couple in the series to have their ship name, Pia, to actually be mentioned on the show. The first was Paige and Alex (Palex), the third was Dave Turner and Alli Bhandari (Bhandurner), the fourth was Sav and Anya (Sanya), the fifth was Winston and Frankie (Frankston), and the sixth was Winston and Goldi (Goldston).
- This was Peter's only relationship of which his mother Daphne Hatzilakos approved.
- They both attended J.T. Yorke's funeral and memorial service at Degrassi in The Bitterest Pill.
- Mia: "I made some big mistakes. I'm really sorry you had to find out like this."
Peter: "It's in the past. I don't care. I like you for who you are now, that's all that counts."
Mia: "You're amazing, did you know that?" - Money for Nothing
- Peter: "I can see myself in your eyes."
Mia: "Like you like how I see you as a person?"
Peter: "No, I can literally see myself. I look good." - If Jay Can't Be Happy...
- First Relationship:
- Second Relationship: