We sought to explore individuals’ motivations for using their direct-to-consumer genetic testing data to generate polygenic risk scores (PRSs) using a not-for-profit third-party tool, and to assess understanding of, and reaction to their results. Using a cross-sectional design, users of Impute.me who had already accessed PRS results were invited to complete an online questionnaire asking about demographics, motivations for seeking PRSs, understanding and interpretation of PRSs, and two validated scales regarding reactions to results—the Impact of Event Scale Revised (IES-R) and the Feelings About genomiC Testing Result (FACToR). Independent samples T-tests and ANOVA were used to explore associations between the variables. 227 individuals participated in the study. The most frequently reported motivation was general curiosity (98.2%). Only 25.6% of participants correctly answered all questions assessing understanding/interpretation of PRSs. Over half of participants (60.8%) experienced a negative reaction (upset, anxious, and/or sad on FACToR scale) after receiving their PRSs and 5.3% scored over the threshold for potential post-traumatic stress disorder on the IES-R. Lower understanding about PRS was associated with experiencing a negative psychological reaction (P values <0.001). Higher quality pre-test information, particularly to improve understanding, and manage expectations for PRS may be useful in limiting negative psychological reactions.