Despite the availability of a safe and effective vaccine being well‐recognized as a critical tool to end the COVID‐19 pandemic, many individuals remain vaccine hesitant for various reasons. In the literature, one well‐established finding is that skeptical attitudes towards vaccination are higher amongst individuals low in conscientiousness. However, no research is available to corroborate whether the relationship between conscientiousness and intention to vaccinate has force in real life. The present research investigated whether, in addition to self‐reported conscientiousness, objectively observable index of conscientiousness behaviors is related to individual perception of vaccination. Based on self‐reported data, Study 1 fully replicated prior findings that higher levels of conscientiousness are associated with more positive attitudes towards vaccination in a Chinese student sample. Using the time of arrival for an appointment as a proxy measure for conscientiousness behaviors, Study 2 revealed that non‐student adults who arrived early to appointments showed stronger COVID‐vaccine uptake intentions than those who arrived late to appointments. Moving beyond vaccination intention to actual behavior, Study 3 found that the arrival punctuality rates of vaccinated participants were higher than those of unvaccinated participants. Overall, our research highlights the important role of conscientiousness‐related traits in individuals' COVID‐19 vaccination attitudes and behavior.