Service workers are expected to maintain high-quality service delivery despite customer mistreatment—the poor-quality treatment of service workers by customers—which can be demeaning and threatening to self-esteem. Although service work is increasingly delivered by middle-aged and older workers, very little is known about how employees across the age range navigate abuse from customers on the job. Does advancing age help or hinder service performance in reaction to customer mistreatment? Drawing on strength and vulnerability integration theory, we proposed that age paradoxically both helps and hinders performance after customer mistreatment, albeit at different stages. We tested our proposed model in a two-sample field investigation of service workers and their supervisors using a time-lagged, dyadic design. Results showed that age heightens the experience of self-esteem threat but, nevertheless, dampens reactions to self-esteem threat, leading to divergent effects on performance at different stages. Implications for age and service work, as well as aging and the sense of self, are discussed.