This study investigates the correlation between the properties of stainless steel 347 samples processed using Laser Shock Peening without Coating (LSPwC). While optimizing the process under different surface confinement conditions, the primary focus is on exploring the synergistic interplay between residual stress, hardness, and microstructural evolution for the selected condition. LSPwC with a water confinement layer at 6 GW cm−2 power density, showed significant Compressive Residual Stress (CRS) of −447.50 ± 48.71 MPa at 60 μm, reaching approximately 76 % of the yield stress and the dislocation density at 60 μm depth is 9.830 × 1014 m−2. Additionally, hardness increased to 256.50 ± 14.15 HV0.1 (∼+53 %) at 50 μm depth. Moreover, there was an increase in the grain boundary fraction to 0.3766 (∼+81 %), along with a rise in the twin boundary fraction to 0.1480. At 6 GW cm−2, correlation analysis revealed a strong relationship between compressive residual stress and hardness (correlation coefficient of 0.972), and between hardness and dislocation density (correlation coefficient of 0.968). Consequently, the 6 GW cm−2 condition emerges as the most practical and effective choice, offering substantial compressive stresses, improved hardness, and efficient grain refinement, and thus favours the 6 GW cm−2 power density condition as the optimal choice for LSPwC of stainless steel 347.