The notion of knowledge internalization (KI), albeit a critical link in Nonaka's (1994) organizational knowledge creation theory, has not been rigorously conceptualized and defined, let alone operationalized. To strengthen the foundation for knowledge management (KM) research, we attempt to fulfill the following research objectives in the three essays of this dissertation. In the first essay, by drawing from Anderson (1983)'s ACT (adaptive control of thought) theory and Glaser et al. (1985)'s framework on the dimensions of cognitive skills, we develop the construct of KI and demonstrate its nomological validity by examining its role in knowledge sharing phenomenon through its relationships with knowledge self-efficacy, expert power, and intention to share knowledge. In the second essay, we apply the KI construct and show that whether people will share their tacit knowledge, measured via expert power, depends on the degree of KI and the extent of a knowledge-based individual-task-technology fit, based on Goodhue and Thompson (1995)'s task and technology fit theory, of which knowledge self-efficacy, preference for personalization KM strategy, accessibility of corresponding KM systems, and task variety, are conceptualized as the underlying components. In the third essay, we profile knowledge workers in organizations using the dimensions of KI, and explore how each profile varies in terms of knowledge self-efficacy, expert power, knowledge sharing intention, and preference for KM strategy. With the three essays, we contribute to KM research by demonstrating that KI is a crucial construct that can help clarify many unresolved issues in KM. To practice, we offer a reliable, easy-to-use, and domain-independent instrument that can be used in evaluating not only the effectiveness of knowledge workers in creating sustainable competitive advantage of organizations, but also success of organizational KM initiatives. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.