The purpose of this case study was to conduct and assess a citywide health promotion campaign in a Japanese suburb community. Specifically, this case report presents a process for planning health promotion campaign, health promotion materials with implementation, evaluation of campaign outcomes, and the problems encountered during our health promotion campaign and their solutions. Our research team planned “Small Change Campaign,” which focused on small lifestyle changes toward being physically active and improving eating behavior by introducing and engaging in health behaviors with low psychological burden and high feasibility. During the initial stages of the campaign, our research team conducted formative research that aimed to identify community health resources and factors that acted as barriers preventing the engagement in health behavior. In addition, a health promotion board consisting of university laboratories, community organizations, and local public health centers was organized for the production, promotion, and evaluation of the health promotion campaign. We provided health information through multichannel (leaflet, newsletter, poster, website, local public relations magazines, health class, events, and online newsletters) for 3 years. Evaluation of positive influence was conducted by post-only one-arm trial with non-randomized cross-sectional study methods. Furthermore, the framework of the continuum of behavior change such as perception of health information, change in attitude and behavioral intention through cognition of information, and trial and maintenance of behavior change was applied.