War broke out in China in 1938, and at once, DBS showed its support towards the Nationalist Party. This was also the year when Mr. G. A. Goodban came to DBS and acted as the headmaster. Goodban provided support in many different ways. He hoisted three flags on the Northern wing of the building; the Union Jack, the D.B.S. flag and the flag of Guomindang. These flags were also placed inside the Hall. Moreover, a Shoe-shining Club was organized to raise funds for the Guomindang. Boys went to schools around Hong Kong, polishing shoes for both teachers and students. They charged them $0.10 each time. As a result, $277.06 was raised.

Anti-Japanese sentiment started in the following years. In 1939, it even led to a school strike when a Japanese student was appointed as Head Prefect.

The school was occupied by the Japanese in the year 1941. Most of the personnel (including Mr. Goodban and the staff) at school were jailed and made to dig an underground chamber to store the ammunition of the Japanese. The building itself was transformed into a military hospital (Kempi Tai to serve the Japanese soldiers). It was also rumoured that the school also served as an execution site for Hong Kong captives.