Educated at Paarl Boys’ High School. Graduated with a Bachelor of Commerce degree from Cape Town University and then undertook postgraduate studies for an actuarial diploma.
After matriculating in Paarl, he studied at the University of the Cape where he obtained his B.Com degree and a Post-Graduate diploma in Actuarial Science. He worked in Cape Town until 1947 when he was appointed Senior Lecturer in Commerce at the University of Cape Town. In 1954 he became an associate professor at that University and in 1956 Professor in Economics at the University College of Rhodesia and Nyasaland in Salisbury.
Principal of the University of Natal, he entered politics in 1966 when he was appointed to the Senate by Prime Minister John Vorster.
He was professor of economics on the Durban campus of the University of Natal and became principal and vice-chancellor from 1965. He was also an adviser on economic affairs to the government of Lesotho. In 1970 he resigned from the university to take up a seat as a Natal-based senator. The then prime minister B.J. Vorster appointed him to the cabinet as Minister of Tourism and Indian affairs in 1972. He was elected leader of the National Party in Natal and held that position until 1984. In 1974 he was appointed Minister of Trade and Industry, and in February 1975 Minister of Finance. On his retirement from politics he held the position of executive chairman of Nedbank until 1993.
He retired from politics in 1984 and moved from Gauteng to Stellenbosch during 1997. Horwood died of a heart attack in 1998 in Stellenbosch.
Economics professor who joined the enlightened verligte camp of the Nationalists when he was wooed into politics as a senator at the age of 53. In cabinet as the representative of the English-speaking Cape Province, he is regarded as having the quiet voice of moderation.