Severe plastic deformation (SPD) is a prominent technique for fabricating ultrafine-grained and nanostructured materials. This study investigates the microstructural evolution and mechanical properties of commercial pure copper processed by two SPD methods: Simple Shear Extrusion (SSE) and Elliptical Cross-Section Spiral Equal-Channel Extrusion (ECSEE). Samples were subjected to four extrusion passes at room temperature using both techniques and subsequently characterized through metallography, microhardness measurements, tensile testing, and forming force analysis. The results demonstrate a substantial enhancement in mechanical properties and grain refinement with an increasing number of passes for both processes. However, the ECSEE method, which imposes more severe plastic strains, yielded superior outcomes. Specifically, after four passes, the ECSEE-processed samples achieved an ultimate tensile strength of 349 MPa and a microhardness of 166 HV, representing an increase of 148% and 9%, respectively, compared to the annealed condition. In contrast, the SSE method, applying lower and more gradual strain, resulted in an ultimate strength of 242 MPa and a microhardness of 139 HV after four passes. Microstructural analysis revealed a 17% and 28% reduction in grain size for the ECSEE and SSE samples, respectively, after the fourth pass. Furthermore, the SSE method benefited from a lower forming force due to its application of lower strain. The findings conclusively indicate that the ECSEE process produces superior microstructural characteristics and enhanced mechanical behavior, including strength, microhardness, and ductility, compared to the SSE method.