Well, de klerk was born(march 1936) in a political family in south africa and that family background played a major role in his political success.
In 1972 he was elected as a member of parliament representing the constituent of vereeniging and re-elected in 1977. In his second term, he held different minesterial posts between 1978 to 1989 prior to being elected president which included posts like minister of national education and planning, minister of mines, energy and environmental planning, among others. When the then president (p.w. Botha) resigned due to illness, de klerk was elected the acting president and later as the president of south africa.
During his early time in office, there was growing sentiment and violent clashes between the xhosa people and the zulu which were fueled by the national security forces, which forces were also accused of gross human rights abuses but de klerk came out and denied authorizing those abuses. On seeing all these he decided to dismantle apertheid, organised for a transition, released political prisoners and organised south Africa's first ever universal vote in which his party(national party) lost to Mandela's ANC. He was elwcted vice president between 1994 to 96 and retired from active politics in 1997. During his time as minister, he defended, supported and enforced apertheid but after the transition he apologised for the evils brought by the system