From 2011 to 2012 he starred as Brandon on the series Retired at 35. His best known role has come starring as Dr. Eugene Porter on the TV series The Walking Dead since 2014. McDermitt has starred in the movies Madison Hall in 2009 and Life in Color in 2015 which he also served as associate producer on. He also had a recurring role as George Payton in the TV series Mad Men in 2014. McDermitt is a member of the Los Angeles improv comedy group Robert Downey Jr Jr. and is a hot air balloon pilot.
