The purpose of the present work is to unveil the effect of very small amounts of Pt loaded onto a NiMn2O4 spinel catalyst on the chemical characteristics and catalytic activity for low-temperature steam reforming (LTSR) of propane. In the H2-TPR curves of the Pt-loaded catalysts, the reduction corresponding to Pt2+ → Pt0 occurred largely at approximately 200–350 °C. It is due to the high accumulation of hydrogen on the PtNi alloy. X-ray photoelectron spectroscopy measurements proved that the PtNi component acted as the active species. The catalysts with Pt loaded on 40NiMn2O4/60γ-Al2O3 show higher propane conversion due to the larger metal interface area created between Pt, Ni, and MnO. In particular, the 40Pt0.025NiMn2O4/60γ-Al2O3 catalyst maintained a very low amount of carbon deposition, a stable propane conversion of 100% and a hydrogen production capacity of 60% at 450 °C, even after 100 h of LTSR.