Rapid urbanization demands construction solutions that are fast, scalable, and structurally reliable. Modular steel structures have emerged as a viable alternative to traditional construction methods due to their prefabrication potential, high strength-to-weight ratio, and ease of assembly. This research presents a comprehensive finite element analysis (FEA) of modular steel components designed for multi-story urban applications. Using ANSYS and ABAQUS simulation platforms, various structural elements—such as columns, beams, floor panels, and modular joints—were modeled under static and dynamic loading conditions. The study focused on stress distribution, buckling behavior, and joint deformation patterns under vertical and lateral loads. Comparative analysis was also performed between welded and bolted connections to evaluate strength, stiffness, and energy dissipation. Results revealed that well-designed bolted modular joints not only facilitate rapid construction but also maintain high structural performance, especially in seismic zones. The simulation data were validated against experimental findings and international design codes (Eurocode 3 and IS 800), confirming the structural integrity and practicality of modular steel systems in urban infrastructure. The study supports the adoption of FEA-driven design strategies for safe, efficient, and rapid deployment of modular steel buildings in densely populated areas