This article discusses a general framework for the analysis of initial/boundary-value problems of rate-independent finite elasto-plasticity based on the theory of Green and Naghdi. A constitutive model is developed within the context of the above theory employing generalized measures of Lagrangian strain and work-conjugate measures of stress. Computational implications of the proposed formulation are discussed in conjunction with an implicit time integrator for the differential/algebraic equations of plastic flow. Representative numerical simulations demonstrate the applicability and predictive capacity of the model in the presence of large plastic deformations.