In this digital age, teachers are novice learners themselves of educational technologies. Pre-service teachers, in particular, face multiple layers of demands and challenges. Not only do they frequently need to learn how to use digital educational tools, but they also may need to adjust their pedagogies, which are directly connected to their beliefs about teaching and learning (Ertmer & Newby, 2016; Tondeur et al., 2017) and their confidence in the practice of technology integration (Hur et al., 2016). Current research lacks insight into pre-service teachers' learning progress during their teacher training and its connection to their ongoing development of contemporary teaching practices that support diverse learning experiences (Ottenbreit-Leftwich et al., 2015). The purpose of this dissertation was to gain further insights into the conceptual changes pre-service K-12 teachers' experience related to technology integration during their teacher preparation that prepares them for future classrooms. The qualitative case study method (Merriam, 2001) was selected in this study to explore pre-service teachers' perceptions and their influences on the "how" and "why" of technology integration practices. This retrospective study examined 69 pre-service teachers' learning trajectories and their conceptual changes related to technology integration within an educational technology course. Guided by learning sciences approaches (Hoadley & Van Haneghan, 2012), a technology integration model (Roblyer & Hughes, 2018), and the ISTE standards (2016; 2018), a qualitative content analysis was conducted through three steps of analysis to triangulate how pre-service teachers construct their perceptions. First, three major themes, ranging from limited use, conservative use, to constructive use of technology, were identified in the pre-course questionnaire analysis, while two main aspects, separated or integrated use of technology, were uncovered in the post-course questionnaire analysis. Finally, three focal participants were purposefully chosen to illustrate their developmental growth and how they translated their beliefs into instructional design. The results of this study offer suggestions and applications for pre-service teacher educators and teacher preparation in designing new approaches to better address the ongoing challenge of technology integration in K-12 classrooms. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]