Embodiments of the present disclosure provide a circuit structure and method for power amplifier control with forward and reverse voltage biases to transistor back-gate regions. A circuit structure according to the disclosure can include: a power amplifier (PA) circuit having first and second transistors, the first and second transistors each including a back-gate region, wherein the back-gate region of each of the first and second transistors is positioned within a doped substrate separated from a semiconductor region by a buried insulator layer; and an analog voltage source coupled to the back-gate regions of the first and second transistors of the PA circuit, such that the analog voltage source alternatively supplies a forward bias voltage or a reverse bias voltage to the back-gate regions of the first and second transistors of the PA circuit to produce a continuously sloped power ramping profile.