He was the leader of the centrist United Party which was the official opposition in the then all-white South African Parliament from 1956 to 1977.

[3][4] His youngest brother was Johannes de Villiers Graaff, a noted South African welfare economist.

Victory in De Villiers' constituency (Hottentots-Holland) was the sole UP gain in the election; nevertheless, Graaff took over leadership of the United Party in 1956 from J.G.N.

He led the opposition to the governments of three apartheid prime ministers, Johannes Strijdom, Hendrik Verwoerd, and B.J.

[3] The M1 highway, which was originally part of a ring road around the southern end of the Central Business District of Johannesburg to the affluent northern suburbs, was named the De Villiers Graaff Motorway in his honour.