At one point in time, Zachary and Victoria Chase dated. When they broke up, Zachary began dating Juliet Watson, a fact that made Victoria jealous. Despite his dating Juliet, Zachary maintained a relationship with Victoria.
When Max Caulfield leaves Mark Jefferson's class, she spots Zachary and Juliet arguing over what she was wearing, and whether or not Zachary had noticed it at all. After the main building was evacuated on account of the fire alarm triggered by Max in order save Chloe Price from being shot, Zachary and the other students were forced outside on account of protocol.
Around some time, Victoria sent Zachary a sext. Victoria used the events that transpired between Zachary and herself to create a lie about Dana Ward sexiting Zachary to turn Juliet Watson against Dana. When Juliet locks Dana in her room she attempted several times to contact Zachary to learn the truth. Zachary ignored her calls. After Juliet learns the entire situation was a lie, she texted Zachary about what she knew about him and Victoria.
Angry, he tells Max, who just left the Girls Dormitory, to "get lost" and throws his football across the way. His football hits Alyssa Anderson, a classmate of Max's. Max has the option of Rewinding time to warn Alyssa about the football Zachary is about to throw. If she does, the football misses Alyssa's head and instead shatters a nearby window.
When Zachary and Juliet finally speak, Zachary tries to claim innocence, saying that he only sexted Victoria as a joke. Juliet, however, didn't believe him and the two presumably broke up.
Following his fallout with Juliet, Zachary speaks with Max at the school. He is caught off guard by seeing Max without her camera in clear view, telling her its weird to see her without her carrying around. Max jokingly tells him she's taking pictures with her eyes.
He uses her comment to segue into the incident with Victoria, asking her not to spread the news of her lie about his sexing Dana around the school. Max tells him that "it was over" and just another moment of drama at Blackwell. Zachary, however, believed the incident was "stupid shit" and didn't understand what Victoria out of it.
Max summarized that Victoria merely wanted attention from the lie. Zachary agreed with her, believing Victoria would draw attention to herself even if it "fucked her over", despite her wealth, beauty and talent. The two decide not speak any further about Victoria and Zachary tells her that he'll see her at the game on Friday. When Max sees Juliet mingling in the hall with Logan Robertson, Max comments that "Juliet is laying the smackdown on Zachary", suggesting that the two are dating.
Later, as Mark Jefferson was lecturing his class on the behavior of the school following the release of the viral video of Kate Marsh, Zachary interrupts, loudly declaring that something was happening at the girls dormitory. Most of the student body follows him out to the girls dormitory, where they find Kate Marsh standing on the edge of the roof. Logan believes Kate has "flipped out" and Zachary is inclined to agree with him just as Kate jumps from the roof and kills herself.
Following the death of Kate, Zachary is one of several students who leave comments on Max's Facebook to blame Max for Kate's suicide. He tells Max, "When we lose a game, no one dies. Just sayin yo". On Kate's facebook, he writes that the Bigfoots would play a game in Kate's memory.
After Max is able to convince Kate to come down from the rooftop, Zachary is one of several students to leave supportive messages on her Facebook page. He writes to Kate, "Blackwell Bigfoots PROMISE to win the next big game for YOU!!!"
When Max and Chloe break into the Blackwell Academy Gym, she has the option of entering the boys locker room. Inside the locker room, Max spots one of Zachary's discarded jerseys lying on a bench next to the lockers. In an open locker belonging to Zachary, she finds his cell phone which features a photograph of Juliet eating ice cream and the sexts that Victoria and Zachary sent to each other on October 7, 2013.
When Max prevents Chloe's father, William from dying in a car accident, she changes the present of her timeline. In the new timeline, Zachary is still attending Blackwell Academy and a member of the Vortex Club. He sits on the ground and appears to be speaking with Nathan Prescott and Courtney Wagner when Max wakes in her new present.
Not unlike Logan, Zachary is a football jock. His silence on matter of Victoria Chase's actions against his ex-girlfriend, Juliet, and her friend, Dana, suggests that he isn't concerned about the consequences of a lying on his fellow students and enjoys spreading rumors until he is caught in a lie by someone he knows.
However, he appears to be distressed during Kate's suicide attempt, and the following night, he leaves a kind and supportive note on her Facebook page. Given the context, it is possible that he is the jock that has "Sorry Kate" written on his dorm room slate.
- Warning Alyssa about Zachary's football will earn the player the "Zoomed In" achievement/trophy if they take a picture of the broken window afterwards.
- In the episode "Out of Time", on the school bus into town, Juliet can be see sitting next to Zachary on the right side of the bus.
- Zachary's last name, "Riggins" is a reference to NBC primetime drama, Friday Night Lights. Mark Jefferson's voice actor, Derek Phillips starred in the series as a character named Billy Riggins, older brother of Tim Riggins.