We connect the quasinormal modes corresponding to Dirac fermions in various curved space-time backgrounds to an N = 2 supersymmetric quantum mechanics algebra, which can be constructed from the radial part of the fermionic solutions of the Dirac equation. In the massless fermion case, the quasinormal modes are in bijective correspondence with the zero modes of the fermionic system and this results to unbroken supersymmetry. The massive case is more complicated, but as we demonstrate, supersymmetry remains unbroken even in this case.The perturbation of a black hole can be achieved either by directly perturbing the gravitational background or by simply adding matter or gauge fields in the black hole space-time. 4 In this paper, we shall use the latter approach, in the linear approximation, which suggests that the field has no back-reaction on the metric. Particularly, we shall study Dirac fermion systems around various black hole and space-time environments and study when the system possesses an unbroken hidden supersymmetry. Supersymmetry has been connected to quasinormal modes spectra in the past, but in a different context. 34-38 Most of these works studied bosonic quasinormal modes and their relation to supersymmetry. We study the zero modes of the fermionic system and directly relate these to the quasinormal modes. As we shall see, the zero modes and quasinormal modes have a bijective correspondence, a fact that can actually be very crucial for supersymmetry to be unbroken. The specific type of supersymmetry that we found is an N = 2 supersymmetric quantum mechanics (SUSY QM) 39-45 with zero central charge. The aforementioned supersymmetry is inherent to many gravitational systems. 46,47 In this paper, the focus is on supersymmetries in gravitational backgrounds. We exploit the existence of the quasinormal modes in this backgrounds in order to establish the fact that, the Witten index of the corresponding underlying supersymmetric algebra is zero, with the kernels of the corresponding operators being nonempty and consequently, supersymmetry is unbroken. This paper is organized as follows. In Sec. 2, we study the supersymmetric underlying structure for the case of a Kerr black hole, with the latter being the most physically interesting black hole satisfying the Einstein's equations. In Sec. 3, we study the massless and massive Dirac fermion in Kerr-Newman, Reissner-Nordström and Schwarzschild gravitational backgrounds. The massive case proves to be much more complicated compared to the massless case, but still, supersymmetry remains unbroken. In Sec. 4, the focus is on three different spacetimes, namely, the D-dimensional de Sitter, Kerr-Newman-de Sitter and Reissner-Nordström-anti-de Sitter space-times, finding the same results as in the previous sections. In reference to the Reissner-Nordström-anti-de Sitter space-time, we find that this fermionic system has two N = 2 SUSY QM algebras. In Sec. 5, we present some physical and mathematical implications of the SUSY QM on the fermionic system and also to the fibe...