Purpose The study aimed to identify the factors impacting nurse unit managers’ knowledge and ability importance of managerial competencies. Methods The participants were 200 nurse unit managers who worked at general hospitals or tertiary care hospitals. Data were collected from February 1 to June 30, 2021, and analyzed using descriptive statistics, independent t-test, paired t-test, ANOVA, and stepwise multiple regression analysis with IBM SPSS/WIN 26.0. Results Nurse unit managers perceived the ability of managerial competencies to be less important than knowledge thereof. Overall, nurse unit managers perceived the importance of human and technical competencies as the most important, while the importance of financial managerial competency as the lowest. The significant predictors of knowledge and ability importance of managerial competencies were ‘nursing environment’ and ‘research experience’, and the input variables explained 34% of knowledge importance and 25% of ability importance. Conclusion Nurse administrators should continue to pay attention to the nursing environment, provide nursing unit managers with opportunities to conduct various research and provide related education.