Purpose <p>While physical activity, sedentary behavior, and sleep have individually been linked to long-term outcomes in cancer survivors, few studies have evaluated their synergistic effects across a full 24-h period. This study aimed to examine the association between adherence to the Canadian 24-Hour Movement Guidelines and mortality risk in a nationally representative sample of US cancer survivors.</p> Methods <p>Data from 2551 cancer survivors participating in the 2007–2018 National Health and Nutrition Examination Survey were analyzed. Adherence to the 24-Hour Movement Guidelines for aerobic physical activity, sedentary behavior, and sleep was summed to categorize participants into four groups. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and cancer-specific mortality.</p> Results <p>The proportions of participants meeting no, one, two, and three guidelines were 14.4%, 38.6%, 34.4%, and 12.6%, respectively. Over a median follow-up of 70&#xa0;months, 617 deaths occurred, of which 261 were attributed to cancer. Compared to those meeting no guideline, HRs (95% CIs) for those meeting one, two, and all three guidelines were 0.72 (0.55–0.95), 0.59 (0.43–0.81), and 0.55 (0.38–0.81), respectively, for all-cause mortality, and 0.47 (0.29–0.76), 0.53 (0.33–0.85), and 0.22 (0.10–0.49), respectively, for cancer-specific mortality. Subgroup analysis showed that the association between cumulative adherence to the guidelines and all-cause mortality was stronger among individuals with a body mass index ≥ 30&#xa0;kg/m².</p> Conclusions <p>Greater integrated adherence to the 24-h movement guidelines was associated with a progressive reduction in mortality risk among US cancer survivors, especially those with obesity.</p>