A parametric controller is proposed for the frequency and phase stabilization after the occurrence of a disturbance in the power grid. The proposed controller is based on the feedback linearization control theory. To drive the frequency of the system generators to stability, the controller relies on receiving timely phasor measurement unit (PMU) readings about the power grid to employ fast-acting flywheels that are situated near the synchronous generators in order to balance a swing equation model of the synchronous generators. The advantages of the proposed controller are that it is tunable and integrates well with existing governor controls in contrast to other forms of PMU-based control. Numerical results show the effectiveness of the proposed controller when applied to the New England power system. Further, a comparison is drawn between the controller and recently-proposed nonlinear controllers for transient stability.