Metallic glass is a heterogeneous composite on the scale of a few nanometers; the structure of the glass on this scale governs its macroscopic thermo-mechanical response. This structure evolves in response to thermal and mechanical loading; this evolution is mediated by discrete kinetic events in which clusters of atoms locally rearrange themselves. We present a model of this structural evolution and mechanical response which consists of a thermodynamic state space, density of states, and models for relaxation and shear transformation events which move the glass through that state space. We implement this model in a homogenized statistical sense and compare to homogeneous relaxation and flow data previously in literature; we also implement it in a discrete mesoscale framework. We conclude with a discussion of gaps in the current understanding of the fundamental structure of metallic glass.