This study describes the TPACK-Developing Instructional Model which prescribes an instructional process for developing pre-service teachers' Technological Pedagogical Content Knowledge (TPACK) during the instruction of Information and Communication Technology (ICT) tools. This model proposes three phases for developing teachers' TPACK through ICT instruction. The phases are: fostering teachers' acceptance and technical proficiency; pedagogical modeling; and pedagogical application. An ICT instructional intervention designed with this model as its framework and its effects on the TPACK development of 74 pre-service teachers were examined. Qualitative analyses of their course reflection comments found that they predominantly developed Technological Knowledge and Technological Pedagogical Knowledge. More emphasis on subject-focused pedagogical modeling, product critique, and peer sharing may better develop their Technological Content Knowledge and TPACK. Future developments of the TPACK-Developing Instructional model are discussed. (Contains 4 figures and 2 tables.)