BACKGROUND: There is an evidence gap about whether a low-risk lifestyle is as important as achieving blood pressure (BP) and random blood glucose (RBG) control. OBJECTIVES: To explore the long-term impacts and relative importance of low-risk lifestyle and health factors on the risk of all-cause and cancer mortality and macrovascular and microvascular complications among patients with diabetes. METHODS: This study included 26,004 diabetes patients in the China Kadoorie Biobank. We defined 5 lifestyle factors (smoking, alcohol drinking, physical activity, fruit and vegetable intake, and waist-to-hip ratio) and 2 health factors (BP and RBG). Cox regression was used to yield adjusted hazard ratios (HRs) and CIs for individual and combined lifestyle and health factors with the risks of diabetes-related outcomes. RESULTS: There were 5063 deaths, 6848 macrovascular complications, and 2055 microvascular complications that occurred during a median follow-up of 10.2 years. Combined low-risk lifestyle factors were associated with lower risk of all main outcomes, with HRs (95% CIs) for participants having 4 to 5 low-risk factors vs 0 to 1 of 0.50 (0.44-0.57) for all-cause mortality, 0.55 (0.43-0.71) for cancer mortality, 0.60 (0.54-0.67) for macrovascular complications, and 0.75 (0.62-0.91) for microvascular complications. The combined 4 to 5 low-risk lifestyle factors showed relative importance in predicting all-cause and cancer mortality and macrovascular complications. CONCLUSIONS: Assuming causality exists, our findings suggest that adopting a low-risk lifestyle should be regarded as important as achieving ideal BP and glycemic goals in the prevention and management of diabetes-related adverse outcomes.