Objective: to examine and describe the relationship between nursing leadership and the quality of care in the hospital environment. Methods: this concurrent convergent mixed methods study incorporated cross-sectional correlational design and grounded theory. Data were collected among staff nurses at a hospital. Quantitative data were collected using the Brazilian Nursing Work Index-Revised/Leadership subscale with 105 nurses and analyzed by descriptive and inferential statistics. Qualitative data were collected through intensive interviews with 64 participants and analyzed by Charmaz’s method. Subsequently, results from both arms were integrated to generate mixed methods findings. Results: better nursing leadership resulted in better quality of care. Qualitative results supported quantitative results and showed that effective nursing leadership yielded quality of care through different processes: collaborating with nursing staff, encouraging patient advocacy, and enhancing care through research. Conclusion: through mixed methods, the findings can be generalized with a deeper understanding about the phenomenon. Implications are also discussed.