By 1800, only a decade after the ratification of the U.S. Constitution, two political parties had taken shape that competed across all levels of government, from the national to the local. How did these parties emerge and consolidate so quickly? I argue that part of the answer lies in political patronage. Using a novel dataset of all civil and military appointments made in the State of New York between 1789 and 1802, together with detailed information on more than 600 state assemblymen who were among the potential recipients of these appointments, I evaluate several competing mechanisms by which office might have been allocated. Regression analyses show that partisanship was the primary factor shaping the distribution of offices—more important than personal characteristics (including seniority, wealth, college education, and legal training), network ties, or regional dynamics. These findings suggest that patronage was systematically used as an organizational resource to reward and discipline allies, create durable channels of coordination, and facilitate structured party-building. The study highlights the fundamental interdependence of state and party formation in the early United States, arguing that early patronage was not a form of corruption but a key mechanism for integrating political actors into the emerging party system.