Person-centered care (PCC) interventions have the potential to improve resident well-being in nursing homes, but can be difficult to implement. This study investigates perceived facilitators and barriers reported by nursing staff to using a PCC intervention consisting of three components: assessment of resident well-being, planning of well-being support, and behavioral changes in care to support resident well-being. Our explorative mixed method study combined interviews (n = 11) with a longitudinal survey (n = 132) to examine which determinants were most prevalent and predictive for intention to use the intervention and actual implementation 3 months later (n = 63). Results showed that perceived barriers and facilitators were dependent on the components of the intervention. Assessment of resident well-being required a stable nursing home context and a detailed implementation plan, while planning of well-being support was impeded by knowledge. Behavioral changes in nursing care required easy integration in daily caring tasks and social support.