Sam Underwood was born on August 4, 1987 in Woking, Surrey, England. He moved to the United States in October 2006 where he studied at the American Musical and Dramatic Academy in New York. He graduated in February 2008.
As well as his appearance on Homeland he is best known to American audiences for his portrayals of Zach Hamilton in the final season of Dexter and for portraying identical twins Mark and Luke Gray on FOX's The Following.
During his time on the latter, he started a relationship with co-star Valorie Curry and as of 2015 the couple is engaged.