An all‐GaN integrated cascode device with an output current of 5 A, threshold voltage of +0.65 V and breakdown voltage of 624 V is demonstrated. Compared with the commercial 600 V hybrid GaN plus Si cascode device (TPH3202), the integrated cascode exhibits a significantly reduced delay time when switched at 200 V and 2.7 A. This is attributed to the absence of a Si metal–oxide–semiconductor field‐effect transistor (MOSFET) driver, leading to a much smaller input capacitance as indicated by the high voltage capacitance measurements. In addition, the integrated cascode device shows a reduced ringing effect due to monolithic integration. When compared with commercial 600 V standalone GaN devices (GS66502B and GS‐065‐004), a reduced Miller effect is observed for the integrated cascode when switched under low gate‐driving current conditions. The results demonstrate the advantages of the cascode device to switch with low gate‐driving current using cheaper, faster, and more efficient gate drivers.