The present study integrates social exchange, role theory, and climate research to suggest that employees who have contact with customers (“contact employees”) will reciprocate felt obligations of high-quality employment relationships (i.e., perceived organizational support [POS]). They do this by expanding their role in ways that are consistent with contextual behavioral expectations. A longitudinal survey of 1,387 contact employees and 666 supervisors in a large supermarket chain in Taiwan demonstrated that the positive relationship between POS and service-oriented organizational citizenship behavior (SOCB) role definitions was strengthened by service climate. In summary, organizational support resulted in expanded SOCB role definitions within a strong service climate, while this relationship was much weaker and not significant in weak service climate. I discuss theoretical and managerial implications through this empirical examination.