The current South Korean government headed by President Moon Jae-in has put a great deal of effort into electricity mix reform by pushing forward the phasing out of coal and nuclear power and the expansion of natural gas and new renewable energy in the country’s electricity generation processes. Noting the importance of understanding public responses to energy policy, the present study segmented the South Korean public according to their preferred direction for electricity mix reform using a nationwide sample. Through a series of latent class analyses, we extracted four distinct segments: Gradual Reformists, Drastic Reformists, Selective Gradual Reformists, and Status-quo Seekers. Overall, apart from the Status-quo Seekers segment (8.75%), support for the transition from coal and nuclear power to natural gas and new renewable energy seems to be the prevailing opinion of the Korean public. However, the degree of such preferences varies across the segments. In addition, regardless of the segment, the South Korean public generally seems to categorize the energy sources in a manner consistent with the underlying framework of the government’s electricity mix reform: they tend to treat coal and nuclear power similarly and natural gas and new renewable energy similarly.