Resonant gate drivers (RGDs) provide low driving loss and high power-density compared with conventional gate drivers. The ability of RGD to adjust switching speed has also received attentions in recent years. Compared with existing active gate drivers, the active controlled RGD has the advantages of fewer components, stronger driving ability and lower driving loss. However, due to the continuous inductor current, the speed adjustment in RGDs are difficult to realize immediate speed adjustment and the speeds between stages will affect each other. A quasi-constant current control method is proposed to eliminate the influence of inductor current continuity between different driving stages. A prototype is designed and four modes quasi-constant current control are realized at different levels of driving current. The active RGD with the proposed quasi-constant current control shows the potential of switching speed adjustment. The collector-emitter voltage slew rate dvCE/dt can be speed up from 6.3 V/ns to 7.3 V/ns at iG changing from 1 A constant current to two-level current of 1 A–1.8 A and slowed down from 8.4 V/ns to 7 V/ns at iG changing from 2 A constant current to two-level current of 2 A–1 A, while the current transition rate diC/dt is well maintained.