Intra-organizational knowledge transfer capability is critically important for achieving competitive advantage through a firm's core competencies. Currently, many firms are implementing knowledge management projects to capitalize on organizational knowledge and leverage it as a foundation for core competencies. Firms are also making generous investments and efforts in Knowledge Management Systems (KMS) as a means for knowledge sharing and transfer, and as a result, organizational members are utilizing knowledge within KMS to apply to their work and generate outcomes, transcending the constraints of time and space. While corporate knowledge transfer has been taking place based on KMS, prior research on knowledge transfer has been conducted without considering KMS characteristics, and although the factors influencing knowledge transfer have been identified to some extent, specific empirical studies and causal investigations have not been concretely conducted. Therefore, this study views the phenomenon of intra-organizational knowledge transfer through KMS as a learning situation, interprets knowledge acquisition from a constructivist perspective that emphasizes learner-centered learning in the information age, and proposes a research model and hypotheses centered on the adoption motivation of knowledge recipients, which were then empirically tested. The reason for treating adoption motivation as a mediating variable is that motivation is a direct predictor of performance; moreover, knowledge transfer in the KMS context requires, above all, the motivation to adopt knowledge; and existing knowledge transfer influencing factors can affect adoption motivation both internally and externally. This study tested hypotheses through a survey of 342 individuals from 81 firms that had implemented KMS. Among the factors influencing knowledge transfer, absorptive capacity, self-efficacy, work pressure, learning culture, system quality, and knowledge quality were found to have significant effects on adoption motivation, and adoption motivation was found to have a significant effect on knowledge transfer success. This revealed that adoption motivation partially mediates the relationship between knowledge transfer influencing factors and knowledge transfer success. However, the moderating effect of trust—that the effect of adoption motivation on knowledge transfer success would differ depending on the degree of trust in the knowledge provider—was not supported. The academic significance of this study lies in the fact that whereas most knowledge transfer research has been conceptual or focused on knowledge transfer between firms or departments, this study focused on interpersonal knowledge transfer by paying attention to the phenomenon of organizational knowledge being rapidly transferred at the individual level through KMS. Additionally, the introduction of a constructivist perspective to knowledge transfer research, the consideration of KMS characteristics, and the examination of the relationship between knowledge transfer influencing factors and success with motivation as a mediator constitute the academic contributions of this study. The practical implications of this study are as follows. Knowledge management practitioners in firms should understand that adoption motivation of knowledge recipients is important in the knowledge transfer phenomenon that occurs voluntarily through intra-organizational KMS, and devise measures to enhance it. Furthermore, given that reward factors were not found to influence the motivation to adopt knowledge, more realistic reward systems should be established, and the finding that both system quality and knowledge quality must be given serious consideration when building KMS represents a practical contribution of this study.