The Korea Superconducting Tokamak Advanced Research (KSTAR) device is an advanced superconducting tokamak to establish scientific and technological bases for an attractive fusion reactor . In-vessel vertical coil (IVC) power supply (PS) is developed for vertical stability and shape control of KSTAR plasma. IVC PS in KSTAR is based on a single-phase full-bridge inverter. The output voltage and current are dc ±1 kV and ±10 kA, respectively. Insulated gate bipolar transistor is used as switching power device in IVC PS and maximal 5 kHz of switching frequency is adopted to meet the requirement of fast control by plasma control system. This paper describes the configuration and engineering of the IVC PS system and analyzes both the IVC coil commissioning and the major performances that D-shape plasma achieved in experiments.