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.

在毕业之前，麦奎尔曾是Playbox剧团的成员，并参与了小型广播剧和莎士比亚作品。当他还是一名戏剧专业的学生时，他第一次受到关注或扮演的角色是在劳拉·韦德（Laura Wade）的讽刺剧《波什》（Posh）的首映式上，他在剧中饰演了“防暴俱乐部”的一名学生成员，这是对牛津大学布林登俱乐部的模仿。