There is growing interest in the use of intersectoral collaboration (e.g., alliances, coalitions, partnerships) to address complex, health-related issues in local communities. Relatively little empirical research, however, has examined how to foster and sustain collaboration across sectors during later stages of development, despite a recognition that the needs and goals for collaboration may change over time. The purpose of this study was to address this gap by examining the perceptions of alliance participants regarding the importance of collaborating with different industry sectors as alliances transitioned from stable, prescriptive foundation support to a more uncertain future. Our findings suggest that, in addition to the contextual characteristics highlighted in previous research, the perceived importance of intersectoral collaboration varies for different types of alliances and participants. Moreover, the salience of these characteristics varied for different types of collaboration, in our case, collaboration with nonmedical health care sectors and nonhealth care sectors. Collectively, our findings point to the importance of thinking more comprehensively, across multiple levels of influence, when considering ways to foster or sustain intersectoral collaboration.