‘Every year Ireland becomes more and more Americanized’, or so the famed journalist W. T. Stead believed at the turn of the twentieth century. But what did people understand by ‘Americanisation’ and who was doing the Americanising? The term was not uncommon in the nineteenth and early twentieth centuries, used by a range of political figures, writers and commentators, typically with reference to mass migration. At the time of Stead’s comment nearly two million Irish-born people resided in the United States. Through their communications and return journeys to Ireland, emigrants became the primary image-makers of America in Ireland, making distinctive interventions in the development of political ideas and organisational models in Ireland. This chapter examines perceptions of the impact of the United States, and Irish America, on Irish politics and how different American influences were welcomed, withstood, filtered, and were in competition with each other in the period from the end of the Great Famine to the 1920s. They made significant contributions to different types of political activity in Ireland, but they were always entangled with a range of other transnational influences.