Purpose: This descriptive research study investigated the effects of temperament and character, emotional intelligence on self-leadership of clinical nurses. Methods: This study recruited clinical nurses at a tertiary general hospital located in S city through convenience sampling. A survey was conducted from April 10 to May 5, 2020, using offline questionnaires. A total of 343 answers were analyzed using descriptive statistics and a three-step hierarchical regression analysis with the SPSS 22.0 program. Results: Factors influencing self-leadership of clinical nurses at a tertiary general hospital in S city were persistent among temperament (β=.331, p<.001), personal maturity (β=.408, p<.001), and total emotional intelligence (β=1.062, p<.001). These factors contributed 58% of self-leadership (F=29.20, p<.001). Conclusion: It was confirmed that persistent among temperament and personal maturity among character, emotional intelligence were factors affecting self-leadership of clinical nurses. Therefore, it is necessary to develop and provide programs to control the factors affecting self-leadership of clinical nurses to increase self-leadership.