Background Colorectal cancer (CRC) remains a major cause of global morbidity and mortality, with rising incidence in younger adults. Growing evidence implicates modifiable lifestyle and environmental factors including diet, physical inactivity, obesity, smoking, alcohol consumption, and pollution exposure in shaping CRC risk. However, existing studies are often fragmented and geographically limited, leaving uncertainty regarding the broader effectiveness of preventive strategies. Methods An integrative systematic review was conducted to synthesize evidence on lifestyle and environmental interventions for CRC prevention. Comprehensive research was conducted through PubMed and CINAHL in 2025 using predefined terms related to CRC, lifestyle behaviors, and environmental determinants. A total of 412 studies were screened, with 15 meeting inclusion criteria after full-text review and quality appraisal using the Newcastle–Ottawa Scale. Data were extracted on study design, population, intervention type, and outcomes, and synthesized thematically. Results The included studies encompassed 267,086 participants across diverse populations and designs, including case–control, quasi-experimental, pilot, and Mendelian randomization studies. Evidence consistently showed that adopting a healthy lifestyle characterized by fiber-rich diets, regular physical activity, smoking cessation, and limited alcohol intake significantly reduced CRC risk. Environmental interventions, such as reducing exposure to pollutants, improving food safety, and ensuring access to clean water, also demonstrated protective effects. Preventive programs integrating lifestyle and environmental strategies enhanced screening uptake, adherence to healthy behaviors, and long-term cost-effectiveness. Importantly, lifestyle modification was found to mitigate even genetically predisposed risks, underscoring its central role in prevention. Conclusion This review highlights the pivotal role of lifestyle and environmental factors in reducing CRC risk. Comprehensive strategies that combine individual behavior change with policy-driven environmental improvements are essential to lowering CRC incidence and mortality. Future research should focus on culturally tailored, long-term, and scalable interventions to achieve sustainable and equitable cancer prevention worldwide.