In this paper, the design of a warm electronics board to provide non-RF control and bias lines to a warm readout system for cryogenic microwave SQUID (superconducting quantum interface device) multiplexing is presented. That system, the SLAC Microresonator Radio Frequency (SMuRF) platform, is a next-generation control and readout system for superconducting microresonators which can be used for a variety of imaging applications ranging from x-rays to Cosmic Microwave Background (CMB) experiments. Focus is given to circuits biasing the cryogenic Transition-Edge Sensors (TES), providing a flux ramp to align the sensor outputs, and circuits to provide software control of gate and drain biases of RF amplifiers in the SMuRF system. Techniques used to reduce the primary components of low frequency noise present in the SMuRF system will also be discussed.