Zac de Beer was born on 11 October 1928. He was the second of four children of Jean Isobel and Zacharias Johannes de Beer, a medical doctor. He attended the Bishops Diocesan College in Rondebosch from 1963 to 45. He completed an MB ChB degree at the University of Cape Town for in 1951.
While at UCT his political career began to take shape. He became active in the affairs of the United. In 1949 he stood for Student Representative Council at the university, becoming its president in 1950 as the candidate of the Student’s Liberal Association. In 1952 De Beer completed his housemanship at Groote Schuur Hospital, and the following year was elected as Member of Parliament for Maitland. At age 23 he became the youngest MP. In 1958 he was re-elected to be an MP under the banner of the United Party. In 1959 he left the United Party to form the Progressive Party (PP). He sold his practice in order to concentrate on politics full-time. He subsequently retained his seat in parliament thus losing it in the 1961 general election. He was offered a job in the advertising and public relations agency that took him to Johannesburg, where he headed the firm’s marketing and research department.
On January 1968 De Beer joined the public relations department at Anglo American Corporation (AAC). After six months he was transferred to the corporation’s headquarters. In 1968 was appointed marketing adviser in the Industrial division. In 1969 he was appointed secretary to the executive committee of AAC.
In 1972 he became chairman of Anglo American Central Africa and lived in Zambia until 1974. De Beer was a director at Anglo America serving on its board until 1988. During this period he briefly returned to politics as MP for Parktown 1977-80. He continued to serve on the finance committee of the Progressive Federal Party (PFP) and was the chairman of Van Zyl Slabbert Trust, renamed Progressive Trust for a New South Africa.
In 1988 he became the leader of the Progressive Federal Party. Under his leadership the PFP, the Independent Party and National Democratic Movement joined forces and formed the Democratic Party (DP). In 1989 he was elected chairman of the newly formed DP. He opened the Convention for Democratic South Africa (CODESA) and later chaired its committee.
He handed over leadership of the Democratic Party (DP) to Tony Leon in 1994 following the first democratic elections in South Africa. He was appointed Ambassador to the Netherlands by President Nelson Mandela shortly after the 1994 general election, but retired because of health reasons.
De Beer died of a stroke on 27 May 1999, at the age of 70 at his Cape Town home.