Abstract: Occasional irregular initial solidification phenomena, including stickers, deep oscillation marks, depressions, and surface cracks of strand shells in continuous casting molds, are important limitations for developing the high-efficiency continuous casting of steels. The application of mold thermal monitoring (MTM) systems, which use thermocouples to detect and respond to temperature variations in molds, has become an effective method to address irregular initial solidification phenomena. Such systems are widely applied in numerous steel companies for sticker breakout prediction. However, monitoring the surface defects of strands remains immature. Hence, in-depth research is necessary to utilize the potential advantages and comprehensive monitoring of MTM systems. This paper summarizes what is included in the irregular initial solidification phenomena and systematically reviews the current state of research on these phenomena by the MTM systems. Furthermore, the influences of mold slag behavior on monitoring these phenomena are analyzed. Finally, the remaining problems of the formation mechanisms and investigations of irregular initial solidification phenomena are discussed, and future research directions are proposed.