The first English Medium High School on the Goldfields opened on 23 January 1957, with 235 pupils enrolled. The school, consisting of prefab classrooms, was situated where Goudveld Hoerskool now stands. The Welkom airfield was behind the school and the whole area was gravel and dust. The staff included Mr J van Huysteen, Acting Principal, and 15 educators. Physical education comprised being issued with a spade and pick and levelling the dustbowl into a sports field! By the beginning of 1960, the roll stood at 306 learners with classes ranging from Grade 8 to 12. 

April 1961 saw the official opening of the new school situated in Falstaff Street. The previous day, the learners carried their desks from the prefab buildings, down Long Road and into their new classrooms. This was similar to a military operation, with the Traffic Department accompanying the learners and educators to ensure that no accidents occurred. The new hall was officially named the J van Huysteen Hall. This was also the first year that a Matric farewell dance was held at the school, organised by the Grade 11 class and educator. Mr van Huysteen retired at the end of 1962, and Mr Eddie East assumed duty as Principal in January 1963. The roll stood at 407 pupils by the end of the first term. In 1965, the school had its first Springbok when Harold Pearce was selected to represent SA against West German swimmers. Mr East focused on improving sports at the school, and Welkom High School became a force to be reckoned with on the sports field. 

In May 1974, the hostel was opened which could accommodate 100 pupils. It rapidly filled up and soon the Department was approached to enlarge the existing buildings. 

Mr East passed away in March 1975 and, in 1976, Mr Angus Pagel was appointed as Principal. The school hostel was renamed the Eddie East Hostel in the same year. By the end of the year the school roll had increased to 830 pupils and Welkom High School was bursting at the seams. 1977 saw the introduction of the first Miss Welkom High School, and the money raised was used to supplement the Grade 11 fund-raising for the Matric farewell. In 1978, Welkom High School celebrated its 21st birthday in the Ferdi Meyer Hall. Present were the 1957 learners, past head boys and girls and educators of 1957, with the guest speaker being Mr Gordon Waddell of Anglo American. 1979 saw the roll dropping to 750 pupils as a result of the opening of Harmony High School; Unitas re-admitting English-speaking learners, and Welkom Prep having its smallest Grade 7 class. 1980 was a great sporting year for Welkom High School. Wayne Tucker, the rugby captain, was selected for Craven Week rugby and made the NFS school team. This was also the year that Welkom High School beat Gimmies 21 – 12 at rugby! At the end of the third term, Mr Pagel resigned to take up an inspectorate position, and Mr N J McGill was appointed Principal in 1981. At this stage, the roll was just over 600 learners: a ratio of 15 pupils per staff member. This certainly allowed for much individual attention and, accordingly, learners benefited. Lyrics for a school song had been sourced by the singing teacher, and Mr Brian Mathieson, a local musician, penned the sheet music for it. A hymn/song book was compiled and introduced at the end of 1981. A new athletics track came into use, which allowed for cricket and athletics to take place simultaneously. The drum majorettes performed extremely well this year while, a successful musical, Dracula Spectacular, was produced to mark the 25th anniversary of Welkom High School. 1983 saw the Welkom High School drummies winning the OFS competition and travelling to Johannesburg to compete nationally. Mr McGill led a cycle tour to East London during the school holidays in order to raise funds and R8000 was collected. In 1984, the building of the Pavilion commenced, which was officially opened as the Angus Pagel Pavilion in August 1986. 

In August 1989, the building renovations started at Welkom High School. A night relay was held which was not only thoroughly enjoyed by all but also managed to raise over R11 000. A musical, ‘Viva Mexico’ was produced in 1990 and played to packed houses at the Ernest Oppenheimer Theatre. The renovations continued apace and slowly more classrooms and a staff room were ready for use. In 1991, the school buildings were officially handed over by the Director of Education, and comprised nine new classrooms, three laboratories, a gym hall and a new administration block. In addition, many classrooms were upgraded. 

1992 saw the introduction of a Model C school. A spring school was organised during the September holidays, and 157 pupils from the townships attended. A musical, ‘Any Dream Will Do’ was produced this year and was very successful. In May 1993, Mr McGill was appointed Superintendent of Education (Mathematics), and Mr M Maree was appointed as Principal. Forty-year celebrations were held this year, and were a great success. A musical, ‘The King and I’ was produced and enjoyed praise from many quarters. The school won the Bewarea Award for the best school garden for undertaking the most conservation, education and beautifying of the city of Welkom. 

In 1995, in the United Nations competition (UN50), McHenry Masitsa was chosen to accompany President Mandela to New York for the UN50 celebrations. This included a visit to Switzerland. 

An ex-learner and educator, Zelda Grobler, organised the 1979 20-year reunion in April 1999, which was very well attended. The 50th anniversary of Welkom High School was celebrated in 2003. Mr Maree retired at the end of 2003, and Mr P Sauer was appointed as Principal in 2004.

In May 2013, Mr. Sauer was appointed at a different school and Mrs. Marion Morrison was appointed as principal at Welkom High School.