1912	The original four room school, named the East Side Public School, was opened by the Port Colborne Board of Education. The school housed both elementary and Secondary School students.
1919	A four room addition to the school was completed.
1957	With the opening of Port Colborne High School, the East Side School became an Elementary school.
1924	An additional four rooms were added to the school to accommodate an increasing student population.
1928	Four more rooms were added to the front of the school. This addition employed a more modern type of architecture and contained office space as well. The school population grew steadily during this period.
1947	An industrial arts shop was opened in the basement to serve all grade 8 students in the city.
1949	Extra classroom space was opened in the basement bringing the total number of classrooms to 21.
1950	The school was renamed in honour of DeWitt Carter, the first mayor of the City of Port Colborne.
1952	The school had a staff of 22. Over 690 pupils from kindergarten to grade 8 were registered here. This was the greatest number of students registered at the school.
1960	The Port Colborne District Association for the Mentally Retarded was granted permission to use basement classroom facilities in DeWitt Carter School. This was a first in the history of Education in the Province of Ontario. The school for retarded children was moved to new facilities attached to Humberstone Senior School in 1973.
1969	The Niagara South Board of Education assumed authority for the operation of the school under the Regional Board of Education Act.
1974	Phase 1 of a major renovations program to improve the facilities and fire safety of the school began. Construction was centered on the second floor level.
1975	Phase II of the renovations program was carried out on the first floor and basement levels. A central library was created. A gymnasium, change rooms, kitchen and office facilities were built. Construction was completed in January of 1976.