Stage work
In February 2007, Walker portrayed Bertram Cates in the Broadway revival of Inherit the Wind. The production opened at the Lyceum Theatre on April 12 and enjoyed a 10-week run to a full house. The show was nominated for four Tony awards, including Best Revival. In April 2008, Walker appeared as the Chevalier Danceny in the Roundabout Theatre Company's production of Les Liaisons Dangereuses. He played the inexperienced lover who becomes the sex pawn of the pernicious La Marquise de Merteuil. Described as the "definitive battle of the sexes" by Broadway World, the production enjoyed a full house and was nominated for six Tony awards.
In December 2007, Walker starred as Andrew Jackson in the musical Bloody Bloody Andrew Jackson during its world premiere at the Center Theatre Group's Kirk Douglas Theatre in Los Angeles. In 2010, he reprised his role in the musical, first off-Broadway at the Public Theater and then at the Bernard B. Jacobs Theatre on Broadway. The musical enjoyed a successful, but short, run. It was also a critical hit, but was nominated for few awards. Walker starred in numerous incarnations of the show to great critical acclaim, including Bloody Bloody Andrew Jackson: The Concert Version (a four-week workshop run at Public Theater in March 2009), and the thrice-extended return at the Public Theater in March 2010. The production closed on January 2, 2011.
From 2012 to 2013, Walker portrayed Brick in a revival of Cat on a Hot Tin Roof. His other stage credits include The Arrangements at the Atlantic Theatre Company (2005), the Lincoln Center Theater workshop of Spring Awakening (2005), Lady Windermere's Fan (2005), Romeo and Juliet (2006), and American Psycho (2016). He received a Tony Award nomination for Best Featured Actor in a Play for his performance in the 2019 Broadway revival of All My Sons.