Throughout much of his time at Degrassi, Peter had trouble fitting in with other boys at school, especially the popular jocks, and had no male friends. He therefore welcomed the prospect of a friendship with Riley, one of the most popular boys at school. Unbeknownst to Peter, Riley was a closeted homosexual and harboured a secret crush on him. Though Peter did not return Riley's affections, he continued to be Riley's closest friend, and provided the support he needed to accept and be comfortable with his homosexuality.
In Man With Two Hearts, Peter and Riley begin spending time together. Peter, who has had difficulty making friends, is eager at the prospect of developing a friendship with the athletic and popular Riley.
Meanwhile, Peter is beginning to pursue a relationship with Mia, who becomes jealous about all the time he and Riley are spending together. Peter, however, is not sure whether he's ready to fully commit himself to a relationship with Mia so soon after his previous girlfriend, Darcy, left Degrassi to go to Kenya.Peter continues to develop his friendship with Riley, much to Mia's frustration. The boys become partners for a science project, and Peter joins the track team.
One afternoon, Peter and Riley skip class to play Wii Sports at Peter's loft. After Riley beats Peter in a boxing game, the boys stop in order to let Riley give Peter some boxing pointers. As they playfully spar, Riley suddenly kisses Peter on the lips. Peter is taken aback and pushes Riley away, and Riley leaves embarrassed, without any explanation as to what happened.
Peter is worried that Riley thinks he is attracted to him, so he decides to become official with Mia in order to have an excuse to stop spending as much time with Riley. During lunch one afternoon, Peter tells Mia that Riley kissed him, and that it scared him. Mia tells Peter that he shouldn't drop his friendship with Riley just because Riley is gay, and that he probably needs more supportive friends.
Peter later finds Riley in the workout room, and assures Riley that even though he is not gay, that he has no problem with Riley's sexuality, and that he's still his friend. Riley fiercely pushes Peter up against a locker, and denies that anything happened between them.
Nonetheless, Peter continues to make an effort to provide support for Riley. When Riley calls him a "fag" in the halls in front of some of their peers, Peter calmly accepts the slur as a joke, and refrains from outing Riley.
In Bad Medicine, Peter becomes concerned when he learns that Riley is using steroids to improve his performance on the football field. Meanwhile, Riley is growing increasingly nervous about being closeted, and begins making attempts to "de-gay" himself. Although he is secretly developing a flirtatious friendship online with Nathan, a gay boy he once went to camp with, Riley asks Anya out for coffee.
Peter and Mia run into Riley and Anya on their date at The Dot. When the girls go to the washroom, Peter asks Riley whether the steroids have made him straight. Riley gets defensive, and says that the kiss between him and Peter was a mistake, and that he likes Anya.
Riley's steroid use begins to make him aggressive and paranoid. When he sees Peter and Danny whispering in class, he is convinced that Peter is outing him to Danny, and violently throws a chalkboard eraser at Peter.
Peter later confronts Riley about his outburst, and insists that he was not talking to Danny about him. He says he has been doing research online about the side effects of steroid use, and that he is worried about Riley's "'roid rage".
When Sav expresses his jealousy about Riley's interest in Anya at a football game, Riley headbutts him in the nose, breaking it. Riley is suspended for three days. As he sits outside Degrassi, Peter brings him his homework for the next several days. Riley tells Peter that he doesn't want to be gay, and he admits that he thought his steroid use would make him straight. Peter sits down with Riley and tells him that being gay does not change who he is as a person.
In Heart of Glass, Riley and Peter work together on a mock UN project for their world studies class.
Season 9In Just Can't Get Enough (2), Riley finds a disheveled-looking Peter in the computer lab, not knowing that Peter had taken meth the night before. He gently pokes fun at Peter's decision to move to Paris with Mia for her modeling career, when the two are interrupted by Declan. Peter tells Declan how sick he feels, which Declan attributes to Peter's meth use. Riley is alarmed by this news, and asks Peter if everything is okay with him. Peter insists that he's fine, and that he will never use meth again.
However, Peter quickly becomes addicted to the drug. He and Mia end their relationship on a sour note when she tells him that she wants nothing more to do with him and his meth habit. Meanwhile, Peter is angry about not getting into Degrassi's music master class. He relieves some of his anger through continued meth abuse.
At the school's winter dance, Peter and his band are scheduled to perform, but Peter does not show up. As the rest of the group starts to play without him, Peter furiously barges into the gym, and yells at them for performing without him. As the rest of the students look on in shock, Peter has a meltdown and runs out of the school. He ends up panicked on a street corner. He phones Riley in a confused frenzy to come find him. Riley and the rest of the Studz track Peter down, and bring him back to his loft. Riley and Spinner Mason stay with Peter that night, and Riley disposes of the rest of Peter's meth.
In Shoot to Thrill, Peter is drug free and happy, and looking forward to making the most out of his single life by spending time with Riley. When Peter asks Riley out for burgers, Riley declines the invite, saying that he's busy with the SAT prep club. The two playfully exchange jokes about being being single, but when Peter makes a joke about Riley's homosexuality, Riley takes offense. Peter apologizes, insisting that he means no disrespect. Riley, who is still positive that he can "straighten" himself out, spots Fiona. He approaches her and the two flirt, while Peter looks on, amused.
In Beat It (1), Riley and Fiona have established themselves as a couple. Although Fiona suspects that Riley is gay, she happily plays the part of his doting girlfriend, as she has no desire for a boyfriend with whom to be intimate, and wants a "bodyguard" to keep other boys from harassing her.
When Riley gets an erection watching Sam, his lifeguarding instructor, perform CPR on a dummy, he gets worried that his peers will realize that he's gay. In a desperate attempt to prove his heterosexuality to everyone, he decides that he and Fiona need to have sex. During gym class, he goes to Peter for advice on how to get Fiona, who says she wants to wait, to have sex with him. Peter tells Riley that if Fiona wants to wait, then there's nothing he can do but be patient. Riley isn't satisfied with this, and invites Fiona over to his house with the intention to have sex with her. Fiona is surprised at Riley's forwardness, and implies that she thinks he's gay. Riley furiously demands that Fiona leave.
Riley's self-loathing continues to manifest itself in aggressive ways. One afternoon, he punches Sam when he innocently asks whether Riley is gay, which results in Riley being kicked out of lifeguarding class.
In Beat It (2), Riley is desperate to find a "cure" for his homosexuality, and comes across a website for a therapist who maintains that he can help Riley choose the life he wants, rather than accept being gay. Excited about the chance to be straight, he tells Peter about the counseling sessions, but Peter has his doubts.
Riley is unable to get enough money to pay for his therapy, so he invites Peter out to try to meet some girls at The Break Room in another attempt to "de-gay" himself. By the end of the evening, Peter has gotten several girls' phone numbers, but Riley has none. While Riley is in the washroom, Sam walks in. He and Riley get into a scuffle, which ends with Riley telling Sam that he isn't "normal", and that he deserves to be beaten up. Sam, who has been open about his own homosexuality with his students, realizes that Riley is gay. Sam tells Riley that although he can't choose his sexual orientation, he can choose when to tell people.At school the next day, Riley decides to start attending anger management sessions with Ms. Sauvé. He meets Peter in the hallway, and finally admits that he is gay. Peter is happy to hear that Riley has come to terms with his homosexuality, and asks whether he should pass the news on, but Riley tells him that he does not plan on coming out in high school. Peter respects Riley's choice, and promises to keep his secret.
- Initially, the producers planned to have Peter and Riley pursue a romantic relationship, which would have made Peter the first bisexual male character in the Degrassi Franchise. The first bisexual character overall was Paige Michalchuk. This distinction was later claimed by Miles Hollingsworth III.
- They have both used drugs: Riley took steroids in Bad Medicine and Peter took crystal meth in Just Can't Get Enough.
- Both Peter and Riley are of Greek descent.
- It's possible that although they were shown interacting little, Riley may have been Peter's closest friend. Peter called Riley instead of his band members when high in Just Can't Get Enough, and from what we're shown, it seemed that Riley stayed by Peter's side the whole night when he was high, whereas Sav Bhandari and Danny Van Zandt left.
- Peter and Riley are the second pair of male friends where one friend who is gay kissed his straight friend. The first were Craig Manning and Marco Del Rossi in Moonlight Desires.
- Officially, Peter was the first person to whom Riley came out in Beat It (2) but Peter was already under the impression that he was gay.
- Because of this, they briefly had a conflict when Riley assaulted Peter for confronting him over the kiss.
- They were both members of the Degrassi Drama Department.
- They both kissed Chantay Black.
- Their friendship is similar of Craig Manning and Maro Del Rossi.