This study aims to examine the self-directed learning ability of pre-service primary teachers taking online English education classes. The research questions were: (1) What are the levels of the pre-service teachers’ self-directed learning abilities? (2) Are there differences in the pre-service teachers’ self-directed learning abilities based on gender and academic achievement? (3) Does self-directed learning ability affect academic achievement and class satisfaction in English education classes? To this end, a survey was conducted among 244 pre-serve primary teachers who took an English education course from 2022 to 2023. The results of the study were as follows. First, the self-directed learning ability of pre-service primary teachers was higher than the average self-directed learning ability of Korean college students. Second, the average of female students was significantly higher than that of male students in all areas, and there was a significant difference between groups in self-directed learning ability according to academic achievement. Third, regression analysis was conducted to examine the impact of self-directed learning ability on academic achievement and class satisfaction, and it was found to be significant, explaining 15.2% of the variance in academic achievement and 6.2% of the variance in class satisfaction. Among the subcomponents of self-directed learning ability, only the cognitive domain was found to have a significant effect on academic achievement. Based on these results, suggestions for future research and education are presented.