The demand for microfeatures in glass substrates has recently increased in radio frequency and microsystems packaging applications. It is primarily due to its favourable properties, including good electrical resistivity, low dielectric losses, and dimensional stability at high temperatures. However, the fabrication of intricate microfeatures on a glass substrate poses challenges due to its hard and brittle nature. Electrochemical discharge machining (ECDM) has been used as a cost-effective solution to overcome these challenges. ECDM is a non-traditional machining technique that utilises electro-discharges resulting from the breakdown of an electrochemically formed gas film enveloping a miniaturised tool electrode. The assistance of ultrasonic vibration was employed to augment the performance of the ECDM method. Herein, the experiments were performed to assess the influence of process parameters (ultrasonic power rating and applied voltage) on the machining performance. The responses evaluated included hole depth and overcut. The results demonstrated the feasibility of UA-ECDM for fabricating diverse microfeatures on glass substrates, making it suitable for high-value manufacturing applications in aerospace, microfluidics, and MEMS.