The purpose of this study was (a) to develop an instructional design model for preservice teachers' learning of technological pedagogical content knowledge (TPACK) in multidisciplinary technology integration courses and (b) to apply the model to investigate its effects when used in a preservice teacher education setting. The model was applied in a technology integration course with fifteen participants from diverse majors. Data included individual participants' written materials and TPACK survey responses, group lesson plans, and the researchers' field notes. The data analysis results revealed that: (1) the participants had difficulties understanding pedagogical knowledge (PK), which hindered their learning of integrated knowledge of TPACK and (2) their learning of TPACK was the combination rather than the integration of PK, technological knowledge, and content knowledge. Suggestions and implications for refining the model and future research possibilities are discussed.