Previous literature suggests a party’s electoral result can shape its vote share and calculus of voting in a subsequent election. Less is known about whether this information-updating process helps explain the success of radical right parties (RRPs) in a multi-level system. To answer this question, I use the case of Germany to test whether a bottom-up spillover effect exists for RRPs. Through a regression discontinuity design, I first find that crossing regional electoral hurdles can substantially improve RRPs’ electoral performance in a subsequent general election. Yet, this positive spillover effect cannot be found for other party families. Next, I use a panel to ascertain which mechanisms drive this effect for RRPs. The analysis suggests the legitimation mechanism is more dominant than the viability mechanism and exposure mechanism. These findings enrich our understanding of both the second-order election framework and RRP studies.