Disclosed is a system for cooling an electronics package. The system includes a fluid pump and a microcooler assembly. The system utilizes one or more cooling layers interspersed with layers of electronics in the electronics package. Each cooling layer has an array of cooling channels formed in a substrate, an input manifold through which cooling fluid is provided for distribution through the array of cooling channels, and an output manifold which collects fluid from the array of cooling channels. The elements of the cooling system are integrated by conduits including a package conduit for passage of fluid from the fluid pump to the electronics package, a cooler conduit for passage of fluid from the electronics package to the microcooler assembly, and a pump conduit for passage of fluid from the microcooler assembly to the fluid pump. Also disclosed is a method for cooling the electronics package.