Students: Perry! Perry! Perry!
— Students at Hiddenville High welcoming Perry
Perry Seinfeld is the brother of Cherry Seinfeld, who lives in Canada and is training to become a hockey pro. Perry came back to Hiddenville in Significant Brother because they were honoring him by hanging his old hockey jersey up at the local skating rink.
Perry is portrayed by Evan Hofer.
Perry is popular and famous. Cherry always gets forgotten by others whenever Perry is around and people always cheer for him when he walks into a room. Cherry mentioned that once, her parents picked up Perry from summer camp and forgot about her.
Perry is also self-centered and ignorant at times. He keeps contradicting Phoebe that they are dating when Cherry confronts them. Even when Cherry is visibly angry to Phoebe for going on a date with her brother, he continues to call Phoebe his "girlfriend" and even asking her if it is the right time for their first kiss.
In Significant Brother, Perry is in town as they are holding a ceremony to honor him and hang his old hockey jersey up at the local skating rink. Perry arrives at Hiddenville High and meets Phoebe and Cherry, amid loud cheers for him.
Phoebe develops a crush on Perry, upon meeting him. A spark is seen when Phoebe shakes his hand and she starts mumbling her name while introducing herself. After an awkward introduction, Cherry returns his hockey stick, that she accidentally took in the morning, to him and ushers him to leave.
Back at the Thundermans' home, Cherry is chatting with Phoebe about a new ice-cream club that just opened. When Cherry leaves for a while, the Thunder Monitor announces that Perry is approaching. Immediately after, the Thunder Monitor announces again whether it should call a doctor as Phoebe's heart just skipped a beat, causing Phoebe to mute it.
Phoebe opens the door and Perry greets her, calling her "Boebe Moebe", which is a reference to Phoebe embarrassing herself during her introduction in the morning. He calls her super sweet and explained that he came to see her, hoping to hang out tomorrow night. Phoebe immediately agreed on the date and starts squealing in excitement after he left.
Afterwards, Cherry is back and correctly guesses that Perry asked Phoebe out as she saw him being flirty with Phoebe in the morning. Unexpectedly, she assumes that Phoebe rejected the date and asks her how Perry's face looked like when she rejected him. Cherry then thanks Phoebe for not dating him, leaving Phoebe dumbstruck. Phoebe then asks her how will it go if she had dated him, which she replies Perry would only think about Phoebe until Phoebe forgets her like everyone else.
Hank and Barb are also big fans of Perry, declaring themselves "#parents4perry" and wants Phoebe to get him sign autographs while Phoebe asks them for their advice on the date with Perry. They advise her to cancel it and keep their friendship.
Phoebe arrives at the local hockey rink early to tell Perry that their date is off. Perry gives her a piece of his campfire sandwich after Phoebe says that she loves it too. She then hopes to have some hot cocoa and Perry completes her sentence before she finishes it, showing that both share common interests. Perry starts to watch the new animated movie about books that come to life, Finding Story, which enticed Phoebe to stay and watch it with him.
Immediately after they finished watching, Cherry arrives and confronts Phoebe. Phoebe denies that she is on a date with her brother, while Perry keeps contradicts her and even calling her his "girlfriend". Perry leaves when both Phoebe and Cherry ask him to keep quiet. Phoebe apologises to Cherry, but Cherry leaves in anger.
At the ceremony, Cherry is still angry at Phoebe, ignoring Phoebe and saying that she has done enough. When Coach Shimeck begins her speech honoring Perry, Phoebe snatches the microphone and starts giving an appreciation speech to Cherry. Both of them reconciled afterwards. Phoebe then makes clear to Perry that she chooses Cherry over him after Perry asks her for their first kiss. Perry looks down after getting rejected and calls for a cheer up chant and the crowd starts cheering for him.
- Perry is one of Cherry's 5 brothers, the others are Harry, Terry, Barry and an unnamed brother.