Teachers are typically abstracted from the design process and not referred to as instructional designers. However, they are constantly designing instruction or adapting instructional materials on a daily basis. Teachers provide a unique perspective as instructional designers: instructional design, content experts, and instruction delivery. Thus, describing their design process is important to help support teachers as they design online courses. This case study examined and described the design process of eleven high school teachers as they designed, developed, and implemented their first online courses. Findings from this study present the online course design processes of these high school teachers and highlight the resources perceived as valuable when embarking on their first online courses. Among the key findings are that teachers face constraints, use a variety of technological tools, and use a variety of pedagogical strategies. Belonging to a community of practice helps online teachers, who report valuing the support of an Online Learning Coordinator. Although given similar guides and resources, they make independent design decisions and rely on feedback from a variety of sources. Recommendations are made for K-12 online learning coordinators, school administrators, and for first-time online teachers/designers related to the processes involved in designing online courses.