Abstract. To understand the time-evolution and thermalization properties of systems like the Quark-Gluon Plasma (QGP), it is necessary to include both weakly and strongly coupled degrees of freedom at various energy scales. Semi-holography is a non-perturbative framework that combines perturbative methods for weakly coupled partons with the holographic duality for the strongly coupled infrared in a wide range of energy scales. I will describe some progress in deriving such a framework from first principles. I will also describe a phenomenological construction aimed towards a better understanding of the QGP and present our recent findings on the collective flow near thermal equilibrium. Our results relate remarkably diverse behavior across a wide range of energy scales.