Based on the ethnographic data collected from the workplace of an academic library, I argue that workplace learning (WL) is a situated socio-cognitive process. It is expedited by knowledge management (KM), which is a collective effort to generate, share, and institutionalize work-related knowledge. KM is inherent in the face-to-face conversational interactions embedded in planned formal training, planned informal sharing, and spontaneous informal learning. When face-to-face interaction is not possible, KM is accomplished through textualization. It helps the members of the workplace acquire new work-related knowledge and integrate it to their common, contextualized knowledge base. The contents of the knowledge base are manifested in the members’ professional practices and explicated by their professional/communal discourse. By virtue of their distinctive practices and discourse, the members form a community of practice (CoP) and gain their professional/communal identity. Whenever they engage in KM, perform their practices, and/or use their discourse, they authenticate their professional/communal identity and enact their CoP.