This study experimentally and numerically examines the performance of low-strength reinforced concrete (LS RC) columns confined with external post-tensioned metal straps (PTMS). Twelve square columns of cross-section 125 × 125 mm and height 1500 mm were subjected to axial load, with eight columns being eccentrically loaded. Four columns were control specimens without confinement, and another eight were confined using a novel technique that provides active confinement through the PTMS. The main parameters investigated included the PTMS confinement ratio (ρ_v = 0.64% and 1.28%) and different eccentricities (e/b = 0, 0.25, 0.5 or 1.0, where e = eccentricity). The results show that the capacity and axial displacement of the PTMS-confined columns increased by up to 43% and 116% over unconfined control columns. Finite element analyses of the columns were carried out in Abaqus® to provide further insight into the behavior of PTMS-confined columns. This study contributes towards developing cost-effective confinement solutions for LS RC columns, thus encouraging the broader adoption of active confinement techniques in practical strengthening applications.