He is best known for his stage work and for portraying Nick Sobotka on The Wire (2003, 2008), William Lewis on Law & Order: Special Victims Unit (2013–2014), Mad Sweeney on the Starz series American Gods (2017–2020), and as George "Pornstache" Mendez on Orange Is the New Black (2013–2017), for which he received a Primetime Emmy nomination for Outstanding Guest Actor in a Drama Series.[5] After high school Schreiber enrolled at the University of San Francisco hoping to win a spot on its basketball team.[14] In October 2012, Schreiber was cast in the recurring role of George "Pornstache" Mendez on the Netflix original drama series Orange Is the New Black.[18] Schreiber was cast as Mad Sweeney in the 2017 Starz series American Gods, based on the novel of the same name written by Neil Gaiman.By the end of season 2, Sweeney remembers that he is Buile Shuibhne, the king of the Dál nAraidi driven insane by the curse of Saint Rónán Finn.[19] In April 2019, he was cast as Master Chief / John-117 in the Halo live-action series, based on the video game franchise of the same name.[21] To prepare for his role in the series, Schreiber worked with a trainer and a chef to bulk up adding muscle to play the supersoldier.In 2016, he co-starred as Kris "Tanto" Paronto, GRS team member and former U.S. Army Ranger in the American biographical war film 13 Hours: The Secret Soldiers of Benghazi, opposite John Krasinski and James Badge Dale.The film was directed and co-produced by Michael Bay, written by Chuck Hogan, and is based on Mitchell Zuckoff's 2014 book of the same name.He played Ray Merrimen, a MARSOC Marine veteran who is the crew's leader and schemer, and one of the robbers who sets out to rob the Federal Reserve Bank of downtown Los Angeles.