A new oak mushroom cultivar Lentinula edodes ‘Eomjisong’ (LE23734), was developed by crossing the dikaryotic and monokaryotic strains of ‘KME36298’ and ‘KME36288-1’, respectively. The optimal temperature for mycelial growth of ‘Eomjisong’ on potato dextrose agar was 23–27°C, and was 15–20°C for fruiting body development. The cultivation period of ‘Eomjisong’ was 131 days, which was 3 days shorter than that of the control cultivar ‘Hanacham’. Morphologically, ‘Eomjisong’ showed stipe length and thickness similar to those of ‘Hanacham’, however, the pileus was larger and thicker. Furthermore, the pileus of ‘Eomjisong’ exhibited higher brightness than that of ‘Hanacham’. Productivity tests showed that the total yield of ‘Eomjisong’ reached 555 g, which was approximately 25.6% higher than that of ‘Hanacham’ (442 g). These findings indicate that ‘Eomjisong’ is a promising cultivar with enhanced productivity and morphological advantages over ‘Hanacham’, suggesting its potential for commercial cultivation.