The insightful investigation of the structural and electronic properties of SmMg and GdMg compounds have been done by Quantum Espresso code using Density Functional Theory. We have employed the first-principles approach, based on the projector augmented wave (PAW) pseudopotentials method, and to solve the exchange correlation, we used Generalized Gradient Approximation of Perdew–Burke–Ernzerhof (GGA-PBE). Our calculated structural parameters, such as equilibrium lattice constant, bulk modulus and the first-ordered pressure derivative of bulk modulus, are well matched with the previously reported experimental data. The electronic band structures, density of states (DOS) and partial density of states (PDOS) plots are drawn to explain their electronic properties. In the calculated electronic band structures, the considerable overlap between the valence band and conduction band of the both materials shows their metallic character. According to our DOS analysis, the primary contributions to the density of states at the Fermi level arise from the d-states. These findings strongly suggest that the d-bands of these atomic energy levels play a vital role in influencing the behavior of these materials.