Based on the theory of purposeful work behavior, this study proposed that the two facets of employee conscientiousness, namely duty orientation and achievement orientation, have opposite effects on pro-social rule breaking (PSRB). We also explored the moderating effect of employees’ task characteristic (job autonomy) and social characteristic (leader reward omission) on the above relationships. Using two-wave data collected from 216 employee-supervisor dyads, we found that duty orientation was positively related to PSRB, while achievement orientation was negatively related to PSRB. Further, job autonomy, by amplifying employees’ perceived meaningfulness of their higher-order implicit goals, can strengthen the positive effect of duty orientation and the negative effect of achievement orientation on PSRB. Similarly, leader reward omission could also activate the negative effect of achievement orientation and PSRB, but not significantly moderate the positive relationship between duty orientation and PSRB. By separating the distinct role of facet-specific personality, our study sheds light on the relationship between employee conscientiousness and PSRB.