This study was aimed at examining the extent to which well-being at work is linked to self-esteem and psychosocial resources such as leader-member exchange (LMX). Drawing on self-determination theory, we looked at whether psychological needs (perceived autonomy, competence, and relatedness) act as specific mediators between self-esteem and well-being, and between LMX and well-being. Two hundred and twenty four employment counselors (psychologists) from a French national employment office (Pôle emploi) answered a questionnaire. The data were analyzed using Hayes and Preacher’s method for testing multiple mediations. The results showed that satisfaction of psychological needs for autonomy, competence and relatedness mediated the links between self-esteem and LMX as inductors, and well-being as a criterion. These findings confirm the relevance of self-esteem and LMX for counselors, and of the importance of need satisfaction that plays a critical role in matters of well-being.