Personality has long been assumed to be linearly associated with safety performance. Focusing on the benefits and costs of personality traits, this study investigates the curvilinear effects of personality traits (i.e., Conscientiousness, Emotional Stability and Extraversion) on safety performance. Results support our hypothesized curvilinear effects that their relationships are initially positive but become negative as personality trait scores increase to extremely high. Furthermore, drawing on theory of purposeful work behavior, this study proposes and finds that the curvilinear effects of personality traits on safety performance are moderated by team level supervisor support climate, such that the inflection points after which the personality performance relationship becomes negative are higher under high levels of supervisor supportive environment than those under low levels of such environment. Implications for research and practice, as well as limitations and directions for future research, are provided.