The University of Johannesburg (UJ), South Africa, initiated a unique Diploma in Accountancy in which ICT has been integrated into the full 3-year curriculum of two of the financial subjects. This integration of ICT into the curriculum of the subjects (Subject Integrated ICT (SIICT)) was the focus of an impact study, analyzed within the framework of Activity Theory, which aimed to identify the impacts that SIICT had exerted on the stakeholders to the diploma. Through empirical data, SIICT has been shown to benefit the students by decreasing study time, enhancing student graduations and bolstering employability. The case study has shown that the successful outcome of SIICT was ensured due to the convergence, planned and unplanned, of three factors: the full integration of ICT into the curriculum of the diploma subjects; the application of Distributed Cognition for Teams (DiCoT) resulting in knowledge-building, measured by the internalization and externalization of the subject knowledge; and, proper and timeous training of the lecturing staff. Using the theory of DiCoT as a baseline and observations of, and interviews with the SIICT lecturers, arguments for a successful conclusion have been presented. One of the primary stakeholders investigated was the lecturers working as a team, and the conclusions link the results of the interviews and observations to the internalization and externalization of the new SIICT subject matter. The case study presents evidence that knowledge building, in the form of DiCoT, is also a leading factor in the successful implementation of SIICT in Accounting. Evidenced in the case study was the co-operation within teams, of three lecturers sharing a subject, which resulted in the creation of common artefacts. Efficient and effective teamwork enhances and strengthens the reciprocal interchange of information within which cognition is shared leading to enhanced internalization and externalization of the subject matter, and a strengthening of the "key distributed cognition attributes". One of the contributions of the case study supported the theory, that there is a correlative relationship between DiCoT and Internalization and Externalization of subject matter, which has been termed "Knowledge building through DiCoT" in the paper.