Food insecurity is a persistent challenge among smallholder farmers, particularly in regions affected by climatic variability and economic instability. This study examines the synergistic effects of combining Climate-Smart Agriculture (CSA) interventions with income diversification strategies in northern Nigeria, using Ordinal Logistic Regression (OLR) across three nested models to explore predictors of food insecurity severity. The three ordinal logistic regression models are: Model 1, which assesses the impact of agricultural interventions on food insecurity; Model 2, which adds income diversification to evaluate its independent effect alongside agricultural practices; and Model 3, which explores the synergistic effects of combining climate-smart agriculture training with income diversification on food security. The Food Insecurity Experience Scale (FIES) is employed to quantify food insecurity, capturing nuanced household-level variations. Data from 128 villages in Kaduna and Katsina states were analyzed to evaluate how integrated approaches influence food insecurity severity compared to standalone interventions. The synergistic model demonstrates that households engaging in both CSA training and income diversification experience an 82% reduction in the odds of severe food insecurity (p < 0.001). This integrated approach outperforms standalone effects observed in other models. Access to improved seeds remains significant across all models, with a 74% reduction in the synergistic model (p < 0.001), compared to 67% in standalone assessments. Similarly, training on regenerative agriculture lowers food insecurity by 49% in the synergistic model (p < 0.01), compared to 44% in standalone models. Micro-mechanization continues to deliver strong results, reducing food insecurity odds by 84% in the synergistic model (p < 0.001), slightly exceeding reductions observed in earlier models. This study underscores the amplified impact of integrating CSA and income diversification strategies, which enhance both agricultural productivity and economic resilience. The findings advocate for policy and programmatic shifts toward synergistic interventions to mitigate food insecurity in vulnerable farming communities.