BACKGROUND: There is an association between surgeon experience and outcomes after cardiac surgery. However, this association is not well studied in the context of patient risk. The purpose of this single-center, retrospective, observational study was to describe how surgeon experience relates to patient risk in isolated coronary artery bypass grafting (CABG) surgery and how this impacts patient outcomes. METHODS: Surgeon experience was defined as time between the surgeon finishing fellowship and date of the patient's surgery. Society of Thoracic Surgeons (STS) Predicted Risk of Mortality (PROM) was used to define patient risk. The Kaplan-Meier method was used to calculate long-term survival, and multivariable Cox proportional hazards regression was used to determine the effect of surgeon experience on survival. RESULTS: Between 2002 and 2018, 7652 patients underwent isolated CABG. STS PROM was 1.35% (interquartile range [IQR], 0.70%-2.80%), 1.55% (IQR, 0.79%-3.34%), 1.78% (IQR, 0.84%-3.84%), and 1.19% (IQR, 0.62%-2.41%) in surgeon experience quartiles 1 (0.01-6.05 years), 2 (6.05-11.5 years), 3 (11.5-16.6 years), and 4 (16.6-32.1 years), respectively (P < .001). For patients in the lowest PROM quartile, Kaplan-Meier survival was similar across surgeon experience groups (P = .66). For patients in the highest PROM quartile, increasing surgeon experience was associated with better survival (P < .001). Cox regression identified surgeon experience as a protective factor (hazard ratio, 0.99, P = .027). In the least experienced surgeon group, increased ejection fraction was a protective factor for long-term survival (hazard ratio, 0.97; 95% confidence interval, 0.95-0.99). CONCLUSIONS: Increasing surgeon experience is associated with higher-risk patients, but the most experienced surgeons take on lower-risk patients. Greater experience correlates with improved outcomes, especially with higher-risk cases.