Breaking through with his portrayal of Mike Wheeler in the Netflix series Stranger Things, he had previously been seen in guest spots in Supernatural and The 100. He was then cast in the 2017 horror film remake It.
The first movie he ever saw was Sam Raimi's Spider-Man.
He enjoys playing the bass and the guitar and has been a member of the band Calpurnia.
He has a brother named Nick Wolfhard.
He played the best friend of Gaten Matarazzo, Noah Schnapp and Caleb McLaughlin's characters in Stranger Things.