The implementation of high voltage enables electrostatic devices to have large output forces and high efficiencies. This work describes research conducted in implementing high voltages in microsystems. The three areas of high voltage generation, actuation, and sensing are used in (i) a platform for untethered insect-size robots and (ii) miniaturized manipulators of high-energy charged particle beams.The first part of this dissertation focuses on developing a multifunctional robot platform with untethered mobility and agility. A new electrostatic actuator architecture and a novel way of delivering power were created, focusing on implementing insect-scale robots. A three-dimensional polymer interdigitated pillar electrostatic (PIPE) actuator was developed, providing a pathway to produce force densities 5-10x higher than biological muscles. The inspiration for the PIPE actuator arises from how skeletal muscles naturally developed to contract, where muscle fibers are intertwined in a 3D honeycomb structure to increase the overlapped surface area. PIPE actuators mimic this 3D structure by packing two chips filled with interleaved pillar arrays. As a result of the increased surface-to-volume ratio, high output force and high energy density can be generated from the PIPE actuator. Typical actuators used in microrobots (including piezoelectric actuators, electrostatic actuators, and dielectric elastomer actuators) require voltage between 0.2-5 kV, making it essential to develop the capability to achieve these voltages in a small form factor. A kilovolt voltage power supply was demonstrated using the pyroelectric effect. This dissertation presented the generation of 1-3 kV pyroelectric voltages with discrete components and integrated printed circuit boards. To overcome the low efficiency of the pyroelectric effect (typically <1%), ambient energy scavenging from the environment can be used. We showed that the pyroelectric high voltage generator (PHVG) can be powered directly by solar light using focusing lenses to drive a cantilever with an actuation voltage of 1.5 kV. An array of PHVGs can also be used to power multiple actuators. A distributed system was explored using fluidic heating to enable the untethered robot to be operated with a flexible body and free of battery recharging. The combination of the PIPE actuators and PHVG power supplies enabled components toward the miniaturization of a micro-robot, which can be employed for tasks that are inaccessible to larger robots, such as investigation and rescue missions in hazardous environments and damaged structures. In the second part of the dissertation, MEMS techniques were employed to develop two novel devices for the study of high energy physics: (i) an electrostatic-based ion beam accelerator and (ii) an ultra-high current pulse generator based on the instability of an electrostatic switch. These projects aim to miniaturize the devices with low costs but large output beam energy/current. The resulted devices pave the way toward miniaturized systems for various applications including plasma and X-ray generation, biological scanning, and semiconductor diagnosis.