Despite the reported success of Lean in health care settings, it is unclear why and how organizations adopt Lean and how Lean transforms work design and, in turn, affects employees' work. This study investigated a cardiology department's journey to adopt and adapt Lean. The investigation was focused on the rationale and evolution of the Lean adoption to illuminate how a department with a long quality improvement history arrived at the decision to introduce Lean, and how Lean influenced employees' daily work. This is an explanatory single case study based on semistructured interviews, nonparticipant observations, and document studies. Guided by a Lean model, we undertook manifest content analysis of the data. We found that previous improvement efforts may facilitate the introduction of Lean but may be less important when forecasting whether Lean will be sustained over time. Contextual factors seemed to influence both what Lean tools were implemented and how well the changes were sustained. For example, adoption of Lean varied with the degree to which staff saw a need for change. Work redesign and teamwork were found helpful to improve patient care whereas problem solving was found helpful in keeping the staff engaged and sustaining the results over time.