<p>This study focuses on the correlation between the uniform distribution of reinforcing phase particles and the microstructure and properties. A TiC-martensitic steel composite with high strength, good plasticity, and impact toughness was successfully prepared using the arc additive manufacturing method with external powder feeding. The results show that when 1 wt.% micron-sized TiC particles are added, they are uniformly distributed. The average grain area decreases from 50.92 to 39.41 μm², the texture strength drops from 12.71 to 6.95, and the texture changes from a single orientation to a random orientation. Without sacrificing plasticity, both the strength and hardness of the matrix increase, and the energy absorption effect in the horizontal direction is improved by 49.2%. The study reveals that the excellent properties of the 1 wt.% TiC-martensitic steel composite mainly stem from the fine-grain strengthening, thermal misfit dislocation strengthening, and load transfer strengthening effects of the uniformly distributed particles. Under external loads, the bonding between the particles and the matrix remains good, and the load energy is transferred to the ceramic particles, causing internal fragmentation and fracture.</p>