This paper investigates the nonlinear mechanics of layered composites that include a stiff elastic constituent and a soft viscoelastic constituent. Layered composites buckle with an infinite wavelength at small compressive strains in the case of a high volume fraction of the stiff constituent (the non-dilute case). An iterative algorithm is derived for the finite deformation of viscoelastic non-dilute layered composites with neo-Hookean phases. After validation by comparison to nonlinear finite element simulations, we analyze the effect of initial layer direction, strain rate, and prestrain on the response to timedependent prescribed compressive strains. Interestingly, these composites have both a very high stiffness prior to buckling and a large energy dissipation capacity in the postbuckling regime. When these composites are subjected to cyclic strains of small amplitude, the effective stiffness and damping properties can be tuned by orders of magnitude by adjusting the prestrain.