Stuhlinger was one of the first group of 126 scientists who emigrated to the United States with von Braun after World War II as part of Operation Paperclip. In the 1945–50 years, he primarily worked on guidance systems in US Army missile programs at Fort Bliss, Texas. In 1950, von Braun's team and the missile programs were transferred to Redstone Arsenal at Huntsville, Alabama. For the next decade, Stuhlinger and other von Braun team members worked on Army missiles, but they also devoted efforts in building an unofficial space capability. He eventually served as director of the Advanced Research Projects Division of the Army Ballistic Missile Agency (ABMA). On April 14, 1955, together with many other Paperclip members, he became a naturalized United States citizen.