It is today commonplace to view radical right parties as masters of their own fates. However, whereas most authors in the field focus on dominant leaders, the impact of party organizations remains understudied. To remedy some of this, we study the impact of three unique measures of organizational development on the electoral performance of the Sweden Democrats (SD) in four consecutive local elections between 2002 and 2014. When controlling for crucial demand- and supply-side factors, while holding the appeal of the national leadership constant, we find that the size, competence, and stability of the local candidate base were all decisive for explaining the success of the SD. These findings suggest that a developed organizational base not only matters to the long-term persistence of radical right parties, but also to their electoral breakthrough. Additionally, we suggest that party organizations are likely to have a greater impact in countries where radical right parties are already established. We conclude by arguing that our findings potentially provide insights into mechanisms that explain how new parties in general establish themselves