This study investigates the dissimilar welding of AISI 1020 carbon steel and AISI 201 stainless steel using the Flux-Cored Arc Welding (FCAW) process. The effects of varying heat inputs (low: 3.5 kJ/mm and high: 5.0 kJ/mm) on the microstructure, mechanical properties, and economic feasibility of the weldments were comprehensively analyzed. Non-destructive testing (NDT), including radiographic inspections, confirmed defect-free welds, ensuring high-quality joints. Microstructural analysis conducted using optical microscopy and scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS) revealed an austenitic matrix with delta ferrite content decreasing from 8.5% at low heat input to 6.8% at high heat input. Hardness testing showed a reduction in weld metal hardness from 227 HV at low heat input to 170 HV at high heat input, while tensile testing revealed ultimate tensile strengths of 749 MPa and 675 MPa, respectively. Fracture analysis demonstrated ductile failure modes, with finer dimples observed at lower heat inputs, reflecting higher ductility. An economic analysis highlighted FCAW's cost-effectiveness for large-scale applications, emphasizing its advantages in terms of labor and material costs. This study underscores the critical role of heat input optimization in FCAW to enhance weld quality, mechanical performance, and economic viability, offering valuable insights for industrial applications involving dissimilar metal welding.