This study aims to clarify the implementation of sustainability certification and its impact on business strategy through a single case study of a small family-run business. In recent years, certification systems have become increasingly important not only for large corporations but also for small and medium-sized enterprises as a means to ensure transparency and reliability. Family businesses, in particular, are gaining attention for their institutional responses and the close relationship between certification and socioemotional wealth (SEW)—non-financial values such as family honor and intergenerational succession. SEW, as a dynamic resource, can influence corporate behavior and potentially contribute to strategic innovation through the adoption of certification systems. The findings reveal that the company voluntarily obtained certifications not only in response to external pressures but also driven by intrinsic motivations such as family pride and contributions to the local community. Moreover, certification acquisition promoted the development of eco‑friendly products, leading to both innovation and enhanced credibility. At the same time, certification systems functioned not only to elevate recognition and external evaluation, but also as a means of communicating the unique values and philosophy of the family business to external stakeholders. This study offers a perspective that reconsiders sustainability certification systems as strategic communication tools. In particular, by focusing on the externally oriented communication function tied to intrinsic motivation in family businesses, it provides theoretical and practical implications for how SMEs may strategically utilize institutional instruments.