Nothing is known about Jonah's life prior to or as the outbreak began.
Jonah is among the Alexandrian children to enjoy the bonfire with Winnie, Linus, P.J. and the other kids from Jocelyn's group. He attends a sleepover at the house Jocelyn and her kids are staying at when in the middle of the night, they all leave Alexandria under the guise of playing a game. In reality, Marcus and the other Alexandrian children, including Judith and Frankie's daughter, were kidnapped. They were brought to a school that Jocelyn's group was staying at when Michonne and Daryl were captured. After they broke free from their binds, they attempt to rescue the children, but Jocelyn's group members usher the Alexandrian children into a trailer, with Mitchell ordering Winnie to kill them all. Fortunately, none of the Alexandrian kids were hurt and they were brought safely back to Alexandria. Upon arriving home, Jonah is hugged by his adoptive parents.
This list shows the victims Jonah has killed:
- Possibly a few zombies
- "Scars" (Flashback)
- According to the actor, the name "Jonah" was assigned to his character, but was never mentioned on the show.