Composite elements have proven efficient in structural applications due to the combined properties of different materials. Recently, high-density polyurethane (PU) foam-filled light gauge (LG) square tubes have emerged as a significant advancement in composite systems. These tubes offer an improved strength-to-weight ratio and provide an economical and sustainable solution for lightweight structural applications, including seismic elements, due to their adequate energy absorption capabilities. Although the structural performance of high-density PU foam-filled LG steel tubes under compression has been demonstrated, a lack of design provisions specifically for PU foam as an infill material globally exists. This study aims to bridge this limitation by evaluating the compatibility of existing concrete-filled tube (CFT) design provisions with experimental results for high-density PU foam-filled LG steel tubes. An empirical model is subsequently developed using multi-nonlinear regression analysis. The results indicate that the width-to-thickness (B/t) ratio and the length-to-width (L/B) ratio play crucial roles in determining compressive resistance, thereby impacting local and global buckling due to geometric instability. This study highlights the importance of both geometric and material parameters in governing compressive resistance and provides design recommendations for construction practices.