This research argues that information technology (IT) capabilities can be classified in macro- and micro-IT capabilities. We propose a conceptual model in which IT infrastructure capability (a macro- IT capability) enables the development of social media and e-business technology capabilities (two micro-IT capabilities) to online engage customers and improve the firm’s customer service performance. We test the proposed model by using the variance-based structural equation modelling technique and the method of estimation of partial least squares employing an innovative secondary dataset on a sample of 100 small firms included in the 2013 Forbes America’s Best Small Companies ranking. The empirical analysis suggests that IT infrastructure capability positively affects customer service performance through two micro-IT capabilities (social media and e-business technology) and social and conventional online customer engagement.