<p>Bangladesh’s tannery industry is a major contributor to export earnings but also one of the country’s most environmentally damaging sectors. In response to increasing regulatory pressure and global demand for sustainable products, biodegradable leather has emerged as a promising eco-innovation. However, there is limited understanding of the factors that influence its adoption at the employee level. This study investigates the determinants of biodegradable leather adoption and its implications for sustainable practice by integrating the Diffusion of Innovation (DOI) theory with the theory of planned behavior (TPB). Data were collected through an online survey of 408 tannery employees working in the tannery. SPSS (v. 25), AMOS (v. 24), and PROCESS Macro (v. 4.2) were employed to test direct, mediating, and moderating effects. The findings reveal that perceived environmental benefit, compatibility, trialability, and observability exert significant positive effects on adoption intention, whereas relative advantage does not demonstrate a statistically significant influence. Adoption intention, in turn, has a strong positive effect on sustainable practice. Mediation analysis confirms that adoption intention transmits the effects of key innovation attributes to sustainability behavior. Moreover, government support significantly strengthens the relationship between adoption intention and sustainable practice, highlighting the importance of institutional backing. By combining DOI and TPB, this study provides a comprehensive explanation of how technological perceptions, behavioral intention, and policy support jointly shape sustainability transitions in a pollution-intensive industry. The findings offer valuable theoretical insights and practical guidance for policymakers and industry leaders seeking to advance SDG-12 by promoting the adoption of biodegradable leather in developing economies.</p>