‘Seongsan’, an early multi-resistant japonica rice cultivar developed from a cross between ‘Jopyeong’ and ‘Jungmo 1012’, was developed by the rice breeding team of the National Institute of Crop Science, Rural Development Administration. The average heading date at the ordinary planting was July 25th in seven test spots. In response to physiological stresses, premature heading rate was very low and viviparous germination rate was relatively low (15.7%). In response to biotic stresses, ‘Seongsan’ showed resistance to bacterial blight pathogen K1 to K3, rice stripe virus, and blight leaf. The milled rice of ‘Seongsan’ was translucent with relatively clear non-glutinous endosperm and medium short grain. The cooked rice had good palatability compared with that of ‘Chucheong’. The milled rice yield of this variety was approximately 5.52 MT/ha in a three-year local adaptability test. ‘Seongsan’ was an early maturing multi-resistant rice with good grain quality, and it was expected to be used as a representative for maturity diversification of rice cultivation area (Registration No. 7277).