In 1909, the school moved to Harmony Street and began to develop. In 1915, the school founded its own kindergarten, opening up opportunities in Chinese education for young children. In 1936, Kuen Cheng was commissioned by the Selangor Department of Education to be an excellent training institution for teachers, and nurtured many outstanding teachers, making great contributions to Chinese education. In 1941 during World War II, the Japanese army invaded the country, and the school was forced to close. After the Japanese surrendered in 1945, the school and its kindergarten were reopened with the support of a group of enthusiastic educators. The school was officially functioning again in 1946. In 1956, the school moved to its current location at Jalan Syed Putra. In 1957, there were 49 students in the first class of graduates. In 1962, Kuen Cheng strived to preserve Chinese education and decided to maintain its position as an independent Chinese school, and its status was officially changed to an "independent secondary school", not receiving any funding from the federal government.