[1] Staf worked as student researcher at the National Agricultural and Forestry College from June 1926 until July 1928.

Staf was appointed as Minister of Colonial Affairs following the death of Willem Kernkamp [nl] and dual served in both positions, taking office on 18 July 1956.

The Cabinet Drees III fell on 11 December 1958 and continued to serve in a demissionary capacity until it was replaced by the caretaker Cabinet Beel II with Staf continuing as Minister of Defence and also took over as Minister of Agriculture, Fisheries and Food Supplies, taking office on 22 December 1958.

Staf remained in active politics, he became a Member of the Senate after the death of Gualthérus Kolff, taking office on 9 June 1959.

In August 1960 Staf announced that he would not stand for the Senate election of 1960 and continued to serve as a backbencher until the end of the parliamentary term on 20 September 1960.