Clinical nurse specialists (CNSs) are vital members of the healthcare delivery leadership team. The knowledge and ex- pertise of the CNS is germane to the quality of care a patient receives. More than 50 CNSs practice at Massachusetts Gen- eral Hospital (the state’s first Magnet hospital), where they share their clinical skills, mentor staff through difficult situa- tions, identify learning needs, and implement innovative ap- proaches to patient care. This article presents a brief history of the CNS role and describes how the CNS role is opera- tionalized at Massachusetts General Hospital and its impact on unit-based and organizational outcomes. In addition, sev- eral programs and interventions identified by the CNSs in re- sponse to results of the Staff Perception of the Professional Practice Environment Survey are discussed. How the CNS influences the professional development of staff and potential implications for the future role of the CNS are described. An exemplar is included depicting a typical work day of a CNS on an acute adult medical unit.