In the years before the Second World War, Rudolf Carnap and Hans Reichenbach emigrated to the United States, escaping the quickly deteriorating political situation on the continent. Once in the U. S., the two significantly changed the American philosophical climate. This two-part paper reconstructs Carnap’s and Reichenbach’s surprisingly numerous interactions with American academics in the decades before their move in order to explain the impact of their arrival in the late 1930s. Building on archival material of several key players and institutions, I take some first steps toward answering the question why logical empiricism became so successful in the United States after the War. This first part reconstructs Carnap’s development between 1923, when he first visited New York, and 1936, when he was offered a position at the University of Chicago. I describe Carnap’s first substantive contacts with American philosophers as well as the events leading up to his decision to emigrate. In addition, I argue that some of Carnap’s work from the mid-1930s—in particular “Testability and Meaning”—can be better understood if we take into account his attempts to correct the American narrative about logical positivism and his increasingly desperate efforts to find a position in the United States.