The rapidly growing research field of additive manufacturing (AM) is an emerging technology that is proving to have the potential to revolutionize manufacturing. The Engineering Directorate of the National Science Foundation (NSF) asked the IDA Science and Technology Policy Institute (STPI) to examine the role of NSF and other U.S. Government agencies in the development and commercialization of AM within the United States. Ultimately, the goal was to discover what lessons can be learned about identifying, nurturing, and promoting emerging science and engineering at NSF, STPI found that NSF played an important role, together with other agencies like the Defense Advanced Research Projects Agency, the Office of Naval Research, and NASA, as well as industry, in creating and maturing the field.