Many studies have explored service innovations regarding the use of information technologies, yet few have addressed the strategic leveraging in IT investment for sustaining competitiveness. The objective of this paper is to examine different strategies that firms have applied in leveraging advanced information technologies for service innovation in highly competitive market. The analysis of strategy is developed based on two dimensions: (1) IT capability, referring to a firm’s ability to deploy IT-based resources, combined with (2) the firm’s complementary resources including customer and supplier relationships, financial capital. We investigate the convenience-store industry and telecommunication industry in Taiwan, are observed to be in the intensive competitive market in terms of the reduced sales growth, intensively innovations undertaken. The case analysis reveals that there are four types of strategies firms apply in leveraging IT for competitiveness: predator, inventor, follower, and hedger. We also found the transition of strategies for IT-enabled service innovation with resource reconfigurated as market evolved. We further identify the resource reconfiguration mechanism occur in the achievement of their sourcing approaches. Generally, this research explains firms’ continuous strategic changes and resource reconfiguration to sustain the advantages of IT-enabled service innovation in competitive market. We suggest a strategy model that includes the issues of the strategy content, path of strategy transitions, resource reconfiguration mechanisms, and resource sourcing approaches. This model provides a guideline for firms to decide their strategies towards different IT-enabled service innovations with the strategic resource configuration changes.