Hydrogen-saturated silicon nanowires (H-SiNWs) are the most attractive materials for nanoelectronics due to their special tunable electronic properties. The incorporation of magnetism in H-SiNWs can be extremely beneficial for a wide range of emerging spintronic devices, which can offer a more effective way to control spin. Here, we investigate the energetic stability, electronic properties, and magnetic properties of transition metal (TM), i.e., Fe and Mn doped Hydrogen-saturated silicon nanowires (TM:H-SiNWs) that have a diameter of 1 nm directed in (100), (110), and (111) facets using spin-polarized density functional theory (DFT). The calculations showed that the TM-doped H-SiNWs (TM:H-SiNWs) convince the electronic and magnetic alterations of H-SiNWs semiconductors. It can be ascertained that the total magnetization of the studied configurations is contributed by the hybridization between a localized p orbital of Si and a d orbital of the TM atoms. In addition, we report the Curie temperature of the TM:H-SiNWs using a mean-field approximation and a Monte Carlo simulation based on the Ising model. We obtain the above room temperature ferromagnetism in the (100) and (111) direction-oriented Mn:H-SiNWs. This study provides an in-depth knowledge of the properties of TM-doped H-SiNWs and can be used as a reference in silicon-based spintronic devices.