<p>High-entropy alloys (HEAs) exhibit excellent mechanical properties and corrosion resistance, making them highly promising for a range of applications. During the electrical discharge machining (EDM) of HEAs, electrode material may deposit onto the workpiece surface, introducing foreign elements onto the processed surface of the HEA. This could lead to uncertain effects on the surface properties of the material. This study investigates the feasibility of EDM using different tool electrodes for Al_0.5CoCrFeNi HEA. When using pure Cu as tool electrodes, Cu elements were deposited on the workpiece surface, while the pure metals that constitute the Al_0.5CoCrFeNi HEA were selected as tool electrodes to avoid the appearance of foreign elements on the machined surface. The recast layer formed using graphite, Al, and Ni electrodes exhibited a higher content of body-centered cubic (BCC) phase and a smaller average grain size compared to those formed using other tool electrodes, leading to increased hardness on the machined surfaces. The Cu electrode exhibited very high material removal rate (MRR) and the lowest relative tool wear ratio (RTWR), but results in medium surface roughness and introduces Cu elements onto the machined surface. The optimal surface roughness was achieved with Co electrodes, with minimized crater depth and recast layer thickness. Therefore, EDM of Al_0.5CoCrFeNi HEA is well-suited for rapid material removal using a Cu electrode, followed by finishing with a Co electrode.</p>