The present research, by using longitudinal data collected in South Korea ( N = 69,986) during the early period of the COVID-19 pandemic (1 January-7 April 2020), examined the pandemic-related changes in the relationship between extraversion and well-being. Multilevel analyses revealed that participants experienced decreased well-being during the pandemic. When analyzing the responses ( n = 3,229) completed during all the periods encompassing the COVID-19-related events (e.g., outbreak of COVID-19), we found the greater within-person decreases in well-being among extraverts than introverts after the intensive social distancing. This finding suggests that social distancing, as a necessary means to curb the spread of COVID-19, inadvertently reduced well-being of extraverts. Implications for the person-environment fit literature, limitations, and future research avenues are discussed.