Background: It is widely reported that facilitation can aid implementation of evidence-based practices. Although scholars agree that facilitators need a diverse range of skills, only a few retrospective studies have identified some of these. During the test of a facilitation strategy within the context of a VA initiative to implement evidence-based care delivery models, we documented the skills an expert external facilitator transferred to two initially novice internal regional facilitators. Ours is the first study to explore facilitation skills as they are being applied and transferred. Methods: Facilitators applied the strategy at eight primary care clinics that lacked implementation capacity in two VA networks. We conducted monthly debriefing interviews over a 30-month period and documented these in detailed notes. External facilitator interviews focused specifically on training and mentoring internal facilitators and the skills that she transferred. We also conducted, recorded, and transcribed two qualitative interviews with each facilitator and queried them about training content and process. We conducted a content analysis of the data, using deductive and inductive methods, to identify skills the external facilitator helped internal facilitators learn. We also explored the complexity of facilitation skills and grouped them into overarching skillsets. Results: The external facilitator helped internal facilitators learn 22 complex skills; with few exceptions, these skills were not unique but overlapped with one another. We clustered 21 of these into 5 groups of overarching skillsets: (1) building relationships and creating a supportive environment, (2) changing the system of care and the structure and processes that support it, (3) transferring knowledge and skills and creating infrastructure support for ongoing learning, (4) planning and leading change efforts, and (5) assessing people, processes, and outcomes and creating infrastructure for program monitoring. Conclusions: This study documented a broad range of implementation facilitation skills that are complex and overlapping. Findings suggest that studies and initiatives planning or applying facilitation as an implementation strategy should ensure that facilitators have or have the opportunity to learn the skills they need. Because facilitation skills are complex, the use of didactic methods alone may not be sufficient for transferring skills; future work should explore other methods and techniques.