As an emerging e-commerce business model, social commerce distinguishes itself through leveraging social media in affecting customer’s purchase decision making. However, in the context of social commerce, the specific mechanism between social media and customer satisfaction, as an important intangible and leading measure of business success, has not yet been fully understood. Based on social capital theory, we develop a model that explains how social media enhance customer satisfaction by facilitating three facets of social capital attainment, i.e. social interaction ties, shared language, and trust, through social presence and interactivity. The social capital would encourage social interaction and collaboration among consumers to exchange domain knowledge and experience, which lead to informed and accurate purchase decision and overall satisfaction lift. This study could provide a new theoretical lens for social media and customer satisfaction research as well as implications for social commerce platform designing and operating.