1960: Kloof High School was founded after Mr Grand Louden and Professor Desmond Clarence established the need for a high school in the upper Highway area.
Mr GMN Goodwin was appointed as the first Principal.
The first annual Sports Day was held at the Luther Field.
1962: Mr JF Dixon became Principal.
The first inter-school sports competitions took place, a Co-Educational Secondary School Swimming Gala and an Inter-High School Athletic meeting
1963: Mr Dudley Barton became Principal.
Construction had begun on permanent buildings.
1964: The pupils of Standards 6 to 9 were able to move into their new classrooms.
1965: The first Standard 10 class wrote the Matriculation examinations and the present school houses, Churchill, Founders and Keller were established.
1969: Mr T. Gerdener, the then Administrator of Natal, officially opened the school.
By then there were 524 pupils and 26 teachers, a further classroom wing including an Art room and Library had been added and a school hall where “William Shakespeare” by Clemence Dane was produced by Mrs Barton.
During the July holidays of that year the first sports tours were undertaken with the 1st Hockey XI touring the Eastern Cape and the 1st Rugby touring Rhodesia (now Zimbabwe). The faith of the founders had been justified and a coat of arms was designed by Mr Alan Woodrow including the motto: “In hoc signo vinces” (In this sign (the cross) you will conquer).
1978: Mr Barton retired and was succeeded by Mr H.M. Puzey.
Further classrooms were built and the school proudly boasts a chapel, computer and video centre, air-conditioned conference room, a drama studio and clubroom for past students, parents and staff.
On the sports front, provincial and, on occasion, national honours, were earned in Swimming, (the school now had a swimming pool), Cricket, Hockey, Athletics and Tennis – some of the varied sporting activities offered at the school.
1989: Mr Hugh Deane became Principal. He encouraged academic excellence and encouraged teachers to be creative in their teaching methods, motivated in regular workshops wherein thinking skills, interpersonal skills, group dynamics and fitting the child for a fast-changing society, were among subjects presented.
The Media Centre was upgraded.
The school serves the community, being used for church services on Sundays, Argus Community School in the afternoons and evenings and hosting several cultural functions.
1993: Kloof High elected to become a state-aided school, with a Board of Governors replacing the Management Council. The Board of Governors is directly responsible for the management of the school, in collaboration with the educators, with direct control of appointment and finances.
1995: Mr Deane was succeeded by Mr David Seager who was Principal until March 2005.
2011: After serving as Acting Principal, Mrs Dawn Lefort took over as Principal.
2019: Mrs Dawn Lefort retired and Mr R.B. Holding took over as Acting Principal.