The coming of World War II is understandably accompanied by a sharp decline in enrollment at Port Credit High School. The student population falls as low as 200. Some march off to enlist; some join the war effort on the home front; still others are needed by their families. Extra-curriculars reflect the times. Both Boys' and Girls' Cadet Corps and the Boys' Bugle Band become prominent features on the playing field.

By the end of the war, as prosperity returns, Port Credit's numbers are once again on the rise. There are more than 500 students and over 20 teachers by 1947. But not everyone who left returns; 26 people, including students and teachers, lose their lives in active service.

Among the changes during the decade is the introduction of Vocational Guidance as a regular part of the program. Music certainly becomes more diverse with the addition of a "Hillbilly Band", and singing proves more popular than ever when 160 voices join Mr. Lankin's choir. The student newspaper is now called The High Light and, as a result of a school-wide contest, P.C.H.S. has its own song. New extra-curriculars include "Clubteen" and the Leadership Club, both introduced in 1948.