To address the large size resulting from gas switches in traditional Marx generators, and the complex drive circuits and high costs of all solid-state Marx generators, this paper proposes a hybrid-switch Marx generator based on MOSFETs and Gas Discharge Tubes (GDTs). A MOSFET replaces the first-stage gas switch in the conventional Marx generator, and subsequent discharge stages use surface-mount GDTs. This hybrid switch architecture enables the sequential triggering of the GDTs using only a single low-voltage trigger signal. It significantly simplifies the triggering circuit and reduces the overall system volume. Based on this approach, a 14-stage Marx generator prototype was developed. Experimental results demonstrate that with a 24-V DC input voltage, the prototype delivers a high-voltage pulse with a peak amplitude of 10.4 kV across a 2000-Ω resistive load. The pulse has a full width at half maximum of approximately 8.5 µs and a rise time of about 9.4 ns (10%–90%). The overall system dimensions are merely 10 cm × 8.6 cm × 5 cm with a weight of 120 g, successfully achieving the goals of significant size and weight reduction for Marx generators.