From Riley Keough to Sam Claflin, Here's Where You've Seen the "Daisy Jones & The Six" Cast Before

Harrison is one of the real newcomers to the cast, playing Graham Dunne, Billy's younger brother and the one who had the idea for The Six in the first place. The actor's only notable prior credits are one episode of the political drama "Madam Secretary" and a movie role in "This Is a Film About My Mother."