Personality has been hypothesized to act as antecedent as well as an outcome of workplace bullying. Still, investigations on the longitudinal relationship between bullying and personality are scarce. We investigated the relationship between accumulated exposure to bullying at work and subsequent changes in psychological hardiness. Additionally, we examined whether hardiness predicted subsequent exposure to bullying. The data were based on the Survey of Shiftwork, Sleep, and Health (SUSSH), a cohort study with annual surveys among Norwegian nurses. The participants who completed standardized instruments measuring exposure to bullying behavior at T1 (2008/09) to T4 (2012) and psychological hardiness at T1 (2008/09) and T5 (2012) were included (n = 938). The results showed that accumulated exposure to bullying (sum of exposure from T1–T4) was associated with reduced psychological hardiness at T5, adjusted for age, sex, and hardiness at baseline (β = –0.16, t = –5.70, p < 0.001). Accumulated exposure to bullying behaviors explained 2.3% of the change in hardiness. Less hardy individuals experienced higher levels of subsequent exposure to bullying behaviors, adjusted for age, sex, and bullying at baseline (β = –0.04, t = –2.21 p < 0.05). Long-term accumulated exposure to bullying behaviors seemed to be a stronger predictor for changes in hardiness as compared to hardiness in predicting exposure to bullying.