Purpose: The purpose of this study was to examine the association of motivation of choosing a teaching profession with teaching self-efficacy and subjective happiness in youth sports instructors. Methods: A total of 262 participants(males 56.9%, females 43.1%) completed questionnaires to assess motivation of choosing a teaching profession(active motivation, material motivation, passive motivation), teaching self-efficacy, and subjective happiness. The data analysis was conducted using descriptive analysis, correlation analysis, multivariate analysis of variance, and confirmatory factor analysis with SPSS 21.0 and AMOS 23.0. Results: Results revealed that there were significant differences in material motivation and teaching efficacy between physical education(PE) majors and non-PE majors. Male instructors reported higher material motivation and teaching self-efficacy than female instructors. Structural equation modeling analysis showed teaching self-efficacy mediated the relation between motivation of choosing a teaching profession and subjective happiness. Conclusion: The results of this study suggest that youth sports instructors’ motivation of choosing a teaching profession should be considered for their quality of life and the quality of education for youth. Also, the strategy to enhance teaching self-efficacy should be involved in the training program for youth sports instructors.