<p>This study aims to conduct an experimental examination into rehabilitating a lightweight aggregate-reinforced concrete beam–column joint with CFRP sheets. Thirteen beam–column joints were employed with dimensions of 250 × 150 × 1000 mm in length, width, and depth for the column and 200 × 150 × 650 mm for the beam. The study’s primary goal is to look at the impacts of different damage ratios (40%, 60%, and 80%) retrofitted with CFRP on the behavior of lightweight aggregate-reinforced concrete beam–column joints under monotonic loads. The findings show that CFRP greatly improves load-bearing capacity, stiffness, and energy absorption, especially at lower damage levels. Configuration-1 of CFRP sheets was the most effective, restoring up to 27% of the load capacity at a 40% damage ratio, but higher damage ratios (80%) demonstrated decreasing effectiveness, with only 7% recovery. CFRP rehabilitation relocated failure modes from the column to the beam, which improved stress distribution and prevented catastrophic joint failure. The study emphasizes the need for early intervention, as CFRP’s potential to restore structural integrity decreases with further damage. Proper application is required for best results, including surface preparation and fiber orientation. These findings point to CFRP as a feasible approach for improving the seismic performance of lightweight concrete structures, particularly in earthquake-prone locations.</p>