The density functional theory was used to explore the structural, electronic, dynamical, and thermoelectric properties of a VIrSi half-Heulser (HH) alloy. The minimum lattice constant of 5.69 (Å) was obtained for VIrSi alloy. The band structure and the projected density of states for this HH alloy were calculated, and the gap between the valence and conduction bands was noted to be 0.2 eV. In addition, the quasi-harmonic approximation was used to predict the dynamical stability of the VIrSi HH alloy. At 300 K, the Seebeck coefficient of 370 and −270 μV.K^-1, respectively, was achieved for the p and n-type doping. From the power factor result, the highest peak of 18 × 10¹¹ W/cm.K² is obtained in the n-type doping. The Figure of Merit (ZT) result revealed that VIrSi alloy possesses a high ZT at room temperature, which would make VIrSi alloy applicable for thermoelectric performance.