<p>This study numerically determines the deformation limits of an electro-thermo-compliant (ETC) microactuator designed for microelectromechanics. Prior investigations have not explored the structural integrity limits of microactuators based on thermo-mechanical-electrical properties, stress-strain-temperature, and stress-voltage relations. A comprehensive 3D multiphysics structural-thermoelectric finite element model was designed. All the mechanisms of heat dissipation for conduction, convection, and radiation were thoroughly considered. We established that the quantity of tip displacement (or put force) can be precisely adjusted by relating it to the applied voltage, grounded on thermomechanical considerations, thus improving the control and efficacy of microactuators. The numerical findings were confirmed by referencing published experimental data. Tip deflection and achievable maximum temperature curves showed nonlinearity for potential differences applied to the anchors. While a linear stress-strain curve was demonstrated, a nonlinear 2nd order voltage effect on stress was shown. The critical voltage level for the melting temperature of silicon at 1750 K was determined. A brittle failure type was observed at approximately 1600 MPa with a 1% failure strain. The thermomechanical modeling technique developed for this microactuator was shown to be versatile and applicable to ETC devices across a broad temperature range (300–1500 K.</p>