Joe Armstrong is the son of actor Alun Armstrong and his wife Sue. He has an older brother, Tom, and a younger brother, Dan, who is in the band Clock Opera. He was born and raised in London, and he attended Elliott School in Putney from 1993 to 1997. He then studied at the University of Bristol where he acted in The Brecht Project—a collection of scenes from the works of Bertolt Brecht—in 1998 and Women Beware Women in 1999.[3] He is a fan of AFC Wimbledon.