Alert systems can engage the community to help locate missing persons with dementia. Evidence on the impact of implemented alert systems is minimal. Guided by three adapted Knowledge-to-Action Framework phases: identifying the problem, assessing barriers, and evaluating outcomes, this study aimed to examine understandings about alert systems and their implementation in Canada, Scotland, and the United States. A document review and interviews conducted with 40 interest holders (those with lived experience, first responders, service providers, and policymakers) underwent thematic analysis. Findings revealed variability in alert systems implementation and barriers at individual (limited understanding of alert systems, privacy concerns, alert fatigue) and organizational levels (sustainability, accessibility, privacy legislation). Participants recommended the following for successful implementation of alert systems: clear policy, collaboration, ongoing assessment, and a localized, opt-in system with accessibility, public education, and sustainable funding. This information indicates under what conditions alert systems for missing persons with dementia could be implemented.