Enhanced usage of digital approaches and Enterprise Social Systems (ESS) in SMEs due to Covid-19 has raised several unanswered questions related to motivation, concerns, and productivity of employees. This study aims to explore the underlying mechanism of knowledge sharing through ESS between motivations, concerns, and productivity. Using a quantitative survey approach this study analyzed 352 employees from Malaysian SMEs. The results revealed that utilitarian and hedonic motivation positively, while privacy concerns negatively influenced employee productivity. Additionally, the mediating role of knowledge sharing using ESS was also proved by study results. Several key policy insights and future research directions are suggested.