Mr Reddiex said 223 year 9 boys were enrolled at the school this year, which was about the third largest intake in the school's history, and the largest in 15 years.
The school was one of several Dunedin secondary schools which created additional year 9 classes this year, following surges in junior enrolments.
Logan Park High School principal Jane Johnson and Kavanagh College principal Tracy O'Brien had also established additional classes of year 9 pupils to meet demand.
Wolfenden and Russell clothing store in South Dunedin was temporarily caught out by the King's High influx.
Manager Gary Roberts said there had been some "pressure" in getting King's pupils outfitted before the school year began because a supplier had not responded to the store's order for uniforms.
He said the school had advised the store last November that the year 9 roll would be about 220-225 pupils, and an order to accommodate the demand for junior uniforms was placed with a clothing manufacturing company.
When the order for stock did not come through, "there was a scramble to get alternative but appropriate stock", he said.
Shorts were temporarily in short supply and some parents were told to come back another day and have their son fitted for their uniform when stock was available. All turned out for the best, and all pupils were in uniform on the first day of school, he said.
Mr Reddiex said the boost in numbers was not expected to create any challenges with fitting the pupils into the school because there was still plenty of room at present.
However, if the roll increase continued for the next two or three years, thought would have to be given to building extra classrooms, he said.
