It has been broadly assumed by both researchers and managers that the more effort salespeople exert, the better their performance outcomes are likely to be. However, organizations are placing an increasing emphasis not just on objective sales outcomes, but on subjective, customer service outcomes as well. This research tests relationships between employee effort and relational performance. We develop and test the position that employee effort reaches a point of diminishing returns, after which relational performance decreases. Further, in an effort to bound our model, we test the moderating role played by employees' emotional intelligence in this relationship. We test our study model in a lagged, multisource field study, matching survey data collected from 107 employees and 19 supervisors, relational performance metrics, and archived effort data collected for a period of 3 months pre–survey data collection. The results from our analysis indicate that the relationship between effort and relational performance is captured by an inverted U-shaped function that is significantly moderated by emotional intelligence. We find that the effort of employees with low EI reaches an identifiable point of diminishing returns; however, the more effort those with high EI exert, the better their relational performance outcomes tend to be.