His first acting job came from Craigslist. Small parts in The 100 and Supernatural followed, then a video audition for an open Netflix casting call landed him Mike Wheeler in Stranger Things (2016). The show became one of Netflix's biggest properties fast. He crossed over to film as Richie Tozier in IT (2017), and by the time he'd done both IT films and two Ghostbusters sequels, his projects had cleared roughly $1.6 billion at the box office combined.
With Stranger Things wrapped after Season 5 in late 2025, he's stepping back from acting deliberately. The plan is music with The Aubreys and a screenplay about The Replacements he's co-writing with his father. He co-directed Hell of a Summer (2023) in 19 days on a small budget, Neon acquired it, and the reviews landed at 49% on Rotten Tomatoes. He hosted SNL in January 2026. At 23, he's more interested in making things than in being cast in them.
His father is a former screenwriter, which partly explains the directing ambitions. He fronted indie-rock band Calpurnia, put out an EP in 2018, then dissolved the band in 2019 and regrouped immediately as The Aubreys with the same drummer. Investors turned down Hell of a Summer repeatedly, citing his age, before 30West financed it. He treated the result as a starting point.