Instructional design and training skills have become a key competency that is expected of public health professionals. However, the research on educating public health students as instructional designers (ID) is lacking. The purpose of this study is to better understand how novice IDs design trainings using their design judgment in an authentic instructional design project in order to provide them with effective educational supports. The data sources of this case study include 11 training lesson plans generated by 37 students through a semester and six semi-structured interviews. The findings reveal that: (1) online games, (2) instructional videos, (3) handouts, (4) PowerPoint presentation slides, and (5) infographics were designed and used by novice IDs. In the midst of the various challenges that were encountered, framing judgment, core judgment, instrumental judgment, navigational judgment, and appearance judgment were manifested in the design process of novice IDs. Based on the findings, practical implementations are recommended to develop effective instructional design curricula for novice public health student designers.