Max Mayfield joined Stranger Things’ main cast in Season 2.
Max is introduced when she moves to Hawkins and begins attending the same school as Mike, Dustin, Lucas, and Will. Known by the arcade name “Madmax,” she quickly establishes herself as an excellent player of Dig Dug and a skilled skateboarder. Her arrival gives the existing group a new friend and creates an immediate romantic rivalry between Lucas and Dustin.
Sadie Sink joined the principal ensemble for the second season, while Dacre Montgomery joined as Max’s older stepbrother, Billy Hargrove. Max’s home life is difficult because Billy is controlling and abusive, but she becomes increasingly important to the group’s fight against the supernatural threats beneath Hawkins.
Max remains a central character in later seasons. In season three, she becomes especially close to Eleven and helps fight the Mind Flayer. In season four, her grief over Billy’s death makes her vulnerable to Vecna, giving her one of the season’s most prominent storylines. She was not part of season one; that is the main reason “Season 1” is a tempting but incorrect choice.