Prior to graduation, McGuire had been a member of Playbox Theatre Company, and was involved in minor radio dramas and Shakespearean productions. While still a drama student, he first came to attention or his role in the premiere of Laura Wade's satirical play Posh in which he portrayed a student member of the "Riot Club", a parody of the Bullingdon Club at Oxford University.
Prior to graduation, McGuire had been a member of Playbox Theatre Company, and was involved in minor radio dramas and Shakespearean productions. While still a drama student, he first came to attention or his role in the premiere of Laura Wade's satirical play Posh in which he portrayed a student member of the "Riot Club", a parody of the Bullingdon Club at Oxford University.
