This work presents the Unified Plastic-Damage-Fatigue (uPDF) methodology developed to comprehensively study the fatigue behavior of metals. The uPDF framework integrates plasticity and damage mechanisms under both monotonic and cyclic loading conditions, providing a robust framework to analyze manufacturing processes and their influence on fatigue life. By combining these load scenarios, uPDF can simulate the deterioration evolution along the material life, enabling the prediction of its remaining fatigue resistance under varying operational conditions. The methodology is based on a plastic-damage model that controls the contributions of plastic deformation and damage degradation. This balance is accommodated based on the active loading scenario to ensure material behavior aligns with experimental observations. One of the key applications of this framework is evaluating the influence of manufacturing-induced effects on fatigue performance. The methodology effectively captures the interplay of the resulting nonlinearities associated with the manufacturing operations, plasticity accumulation, and damage propagation, demonstrating its potential to predict life expectancy in components. Several case studies are presented to validate the methodology’s effectiveness. These examples illustrate the versatility of the uPDF approach in simulating complex loading scenarios. The results highlight the potential of this methodology to improve fatigue life predictions and provide critical insights into enhancing the durability of metallic materials under real-world service conditions. This unified approach represents a significant advancement in the field of computational fatigue analysis.