Mitral Regurgitation (MR) results in a backflow of blood during systole, which imposes a volume load on the ventricle, resulting in a sequence of adaptations and modifications in the left ventricle. Recently, Finite Element (FE) models have been used to investigate the biomechanical features of the mitral valve due to MR and to understand its effect on the left ventricle. In this study, a realistic 3D FE model of the Left Ventricle (LV) was coupled to a closed–loop lumped parameter circulatory model in which backflow owing to MR was incorporated. To examine the biomechanical behavior of the left ventricle, simulations were executed on both a model of a healthy heart and a model of a heart with progressively severe mitral regurgitation. The overall LV mechanics for different simulation cases were assessed by quantifying the LV pressure-volume loop, ejection fraction (EF), circumferential and longitudinal strain variations. For the pressure-volume loop, as the MR severity grew, the peak LV pressure dropped and the LV stroke volume increased, which in turn increased the ejection fraction. Circumferential strain likewise increased, whereas longitudinal strain remained unaffected. Simulations were also run for severe MR cases with increased LV wall thickness to investigate the effect of both MR and LV hypertrophy on overall LV mechanics. The PV loop significantly shrunk down as the LV wall thickness was increased. In addition, for severe MR cases simulations were also performed by varying LV preload and afterload to assess the effect of LV loading conditions on EF. This study demonstrates that FE modelling is a valuable means to apprehend the biomechanics of the regurgitated left ventricle, which may be utilized to simulate different parameters impacting the regurgitated heart and assist medical professionals in making more informed judgments.