INTRODUCTION: Transportation and land-use policies can affect the physical activity of populations. Local health departments (LHDs) are encouraged to participate in built-environment policy processes, which are outside their traditional expertise. Cross-sector collaborations are needed, yet stakeholders' perceptions of LHD involvement are not well understood. The objective of this study was to describe the perceived value of LHD participation in transportation and land-use decision making and potential contributions to these processes among stakeholders. METHODS: We analyzed qualitative data from 49 semistructured interviews in 2015. Participants were professionals in 13 US states and 4 disciplines: land-use planning (n = 13), transportation/public works (n = 11), public health (n = 19), and other (municipal administration and bike and pedestrian advocacy [n = 6]). Two analysts conducted directed content analysis. RESULTS: All respondents reported that LHDs offer valuable contributions to transportation and land-use policy processes. They identified 7 contributions (interrater agreement 91%): 1) physical activity and health perspective (n = 44), 2) data analysis and assessment (n = 41), 3) partnerships in the community and across sectors (n = 35), 4) public education (n = 27), 5) knowledge of the public health evidence base and best practices (n = 23), 6) resource support (eg, grant writing, technical assistance) (n = 20), and 7) health equity (n = 8). CONCLUSION: LHDs can leverage their strengths to foster cross-sector collaborations that promote physical activity opportunities in communities. Our results will inform development of sustainable capacity-building models for LHD involvement in built-environment decision making.