This chapter examines the integration of climate-smart agriculture (CSA) and sustainable land management (SLM) practices and their impact on agricultural sustainability. Through comprehensive analysis of empirical evidence across diverse agroecological zones, we evaluate how these complementary approaches collectively enhance food security, soil health, and climate resilience. Our research reveals that CSA implementation significantly increased productivity from 2.8 to 35.6 t ha−1 and net returns from USD 359 to over USD 3500 ha−1, achieving a sustainability index of 0.89. Analysis demonstrated that soil biodiversity strongly correlates with ecological multifunctionality (R2 = 0.147, p < 0.01), underscoring its critical role in sustainable agriculture. CSA adoption varied significantly by region, with Cameroon showing higher implementation rates (69.2% for crop rotation, 65.3% for intercropping) compared to Kenya (42.1% and 41.5%, respectively). The research confirmed that CSA practices like crop rotation increased rice yield by 1.98–2.54 quintals per acre, while integrated soil management enhanced productivity by 2.59–3.01 quintals per acre, resulting in 27–34% increases in net agricultural income. In sustainable yield analysis, dairy units (0.77) and mixed crop–livestock systems (0.84) demonstrated the highest sustainability, while fisheries showed the lowest (0.28) due to flooding vulnerability. Furthermore, SLM practices provided 1.7–1.9 times greater economic value from ecosystem services compared to conventional methods. Future work should focus on overcoming adoption barriers through integrated policy frameworks, technological innovation, and enhanced stakeholder engagement to scale these practices effectively across diverse agricultural contexts worldwide.