Physical education (PE) is beneficial for the development of elementary school-age children through its promotion of different educational learning outcomes, which in turn affects the long-term development of physically active lifestyles. In many countries, PE is taught by classroom teachers (CTs), who are thought to be in a unique position to positively impact students’ learning. While a substantial body of studies examines the challenges that CTs encounter when teaching PE, less research has been directed towards gaining a comprehensive understanding of how CTs visualize PE and, in turn, how to promote various types of PE. The purpose of this study, therefore, was to explore elementary school CTs’ beliefs about and practices in PE in South Korea. To achieve the research goal, a semi-structured face-to face interview with six CTs was performed to collect the qualitative data source, using the ground theory as an analysis method. Three themes emerged from these interviews concerning the CTs’ beliefs in PE: (a) the importance of understanding students’ characteristics, (b) the importance of centering internal perceptions in PE method, and (c) the importance of meaningful experiences. The results also identified two themes for teaching practices in PE that corresponded to CTs’ beliefs: (a) crafting personalized instructional methods and (b) connecting PE experiences. This study lends important insights to future practices and research recommendations for CTs’ PE teaching and teacher education programs.