Secondary education began in Opunake in 1920 with nine students being taught at St. Barnabas Church Hall however this arrangement only lasted a couple of months as some pupils left school and there were insufficient numbers to warrant continuing. By 1924, the Headmaster of the primary school and secretary of the School Committee canvassed the district and found enough students to open a Secondary Department in one small room placed on the primary school grounds and thus in 1925, Opunake District High School was born with the name remaining for the next 30 years. The roll quickly grew to 57 students and by 1928, a block of buildings consisting of one classroom, a laboratory, a cooking room and a woodwork room were built on the current High School grounds.
In 1929, the motto “Ut Prosim Patriae” (That I may be of use to my country) as found on our current crest was adopted. For the next 25 years, secondary education kept rolling on. In 1951, the East Wing and Administration buildings were opened, in 1954, the school baths were complete.
In 1956, the Secondary Department of the Opunake District High School and grown big enough to formally become a full High School, and the first Principal of Opunake High School – Mr R.C. Griffiths was appointed to the role. Over the next ten years, a North Block was added (1958), tennis and basketball courts were completed, the Assembly Hall opened (1962) and the Hill Wing completed also (1963).
In 1964, Mr B.V. Cooper was appointed Principal. W.D.R Currey (PE Teacher) became the first in a long line of students or staff members to represent New Zealand by being selected to the All Blacks.