John Gallagher Jr. has appeared in several television programs, including The West Wing: Im Zentrum der Macht (1999), Law & Order: Special Victims Unit (1999), New York Cops: NYPD Blue (1993), Ed - Der Bowling-Anwalt (2000), Love Monkey (2006), and Hallmark Hall of Fame's film The Flamingo Rising (2001). He played Jim Harper in Aaron Sorkin's The Newsroom (2012) which aired on HBO. He also appeared in HBO's mini-series Olive Kitteridge - Mit Blick aufs Meer (2014), based on the Pulitzer-winning novel of the same name, in the role of Christopher Kitteridge.
Film credits include Pieces of April - Ein Tag mit April Burns (2003), Woody Allen's Whatever Works - Liebe sich wer kann (2009), Jonah Hex (2010), The Heart Machine (2014), Kenneth Lonergan's Margaret (2011), and a lead role in Short Term 12 - Stille Helden (2013) opposite Brie Larson. In 2016, he starred in the thriller film 10 Cloverfield Lane (2016) and the horror thriller film Hush (2005).
