•CNSs identify clinical problems and initiate system-level clinical projects.•CNSs are clinical experts; the better the expert work the less visible it becomes.•CNSs work is articulation; managing intersections of people, technology, organizations.•Articulation work was facilitated by self-agency, trust, influence.•Explains why the CNS role is often considered invisible and ambiguous. Advanced practice registered nurses (APRN) are expected to contribute to improved patient outcomes. Traditionally, clinical nurse specialists (CNS) have been the APRN role that led system-level nursing practice initiatives to advance care for specialty populations. Little is known about the work processes used by CNSs to achieve outcomes. This study identified common processes used by CNSs working in a variety of practice settings and specialties to advance nursing practice and achieve improved clinical outcomes. Qualitative descriptive methods were used; a purposeful sample of CNSs with completed system-level projects participated in focus groups. Data were analyzed using standard content analysis process. CNSs engaged in intricate interactions identified as articulation work involving the management of intersections between people, technology and organizations. This expert work is largely invisible. Self-agency, trust, and influence are a nexus upon which CNS work processes revolve. The findings provide insight into CNS work processes, lend credibility to the CNS's leadership abilities, and help explain why the CNS role and practice is often considered invisible and ambiguous.