First principle method based Density functional theory calculations are used to investigate electronic, magnetic, thermoelectric and lattice-dynamical properties of Full-Heusler compound Mn2MgGe. We considered the energetic, thermodynamical and lattice-dynamical stability criteria for Mn2MgGe by evaluating the total energy, formation energy, and phonon density of states respectively, which thereby suggest that the synthesis of Full-Heusler compound Mn2MgGe is possible. Half metallic spin-polarized nature from electronic band structure and total magnetic moment (2μB) of Hg2CuTi type structure of Mn2MgGe potentially facilitate its spintronics applications. The results of electronic structure and magnetism predicts that Hg2CuTi type structure of Mn2MgGe is an indirect band gap semiconductor with half-metallic ferrimagnetic behaviour. Antiparallel and equal magnetic moment of Mn atoms cancel out the magnetization in Cu2MnAl type structure of Mn2MgGe, making its total magnetic moment 0 μB/cell. The electronic and magnetic properties for Cu2MnAl type structure of Mn2MgGe has not been previously reported. Positive and negative value of Seebeck coefficient for spin up and spin down channel indicate the presence of P-type and N-type charge carriers in the compound. Mn2MgGe exhibits high Seebeck coefficient −38 μV/K and 180 μV/K in spin-up and spin-down channel at room temperature (300 K) along with huge power factor of 4.23×1011 w/mK2s at 600 K, predicting Mn2MgGe as a potential candidate for thermoelectric applications.