Additive manufacturing using directed energy deposition (DED) is an advanced technology that facilitates the creation and repair of complex metal parts. This technique is particularly convenient for high-performance applications due to its flexibility in material choice and its capability to manipulate microstructure. However, the significant thermal gradients inherent in DED can result in residual stress and dimensional distortions. To better understand these challenges, this study introduces a newly developed numerical model designed to simulate the thermal distribution during deposition and assess the mechanical behavior of the deposited material. The model’s validity was confirmed through comparisons with existing literature, allowing for accurate predictions of thermo-mechanical behavior based on available experimental data on temperature and deformation. The findings reveal a strong correlation between the obtained results and those reported in previous studies, illustrating how improved simulation accuracy can lead to a deeper understanding of the DED process, enabling the optimization of process parameters and enhancement of the quality of manufactured components.