He was the only son of Pieter Willem and Hendrina Prinsloo-de Wet (he had nine half-sisters). His father fought as a commando against the British in the Second Boer War (1899–1902), while his mother was interned in a British concentration camp.
Botha became a member of the National Party while studying law at the University of the Orange Free State. At the age of twenty-one he dropped out of university to take up the post of National Party organizer in the Cape. He was elected to national parliament in 1948.
On becoming Prime Minister in 1978, he faced rising resistance from the black population, economic instability, sanctions, and international condemnation of apartheid. This was coupled with drought, a fall in the gold price, an escalating defense budget, and the National Party’s fear of rising communist influences in South Africa and neighbouring countries. To counteract the 'total onslaught' against South Africa, Botha developed a 'total strategy' to address political, economic, military and security issues. At a conference in Upington in 1979 he warned white South Africans that they would have to 'adapt or die.'
Botha attempted to modify certain aspects of apartheid to introduce reforms, but planned only to share a measure of power while retaining National Party, and white minority, control of government. He set in motion the dismantling of some apartheid legislation in the early 1980s. However, increasing violence and civil insurrection across the country from 1984 saw Botha declare a state of emergency, ban activists and liberation movements, and consolidate his power at Executive State President. In February 1989, he suffered a mild stroke and, under pressure from cabinet, resigned.