Primary schools and secondary being studied the Chaux-de-Fonds, Bern and Neuchâtel, of right and commercial and administrative sciences in Neuchâtel. Lawyer in Lausanne in 1933. As of this date, Graber is very committed in the political life and assumes many electoral mandates.

Of an acknowledged ambition, it climbs all the levels of the course honorum. To advise communal (legislature) socialist (1934-1945), appointed with the Great Council of Vaud (1937-1946). New French secretary of the Swiss socialist party, it must face the scission nicolist of 1939 and reconstitute the French socialist parties.

Syndic of Lausanne (1946-49), it is in charge of the socialo-popist municipality. There remains municipal finances until 1962. State Counsellor (Finances, 1962-1970). To advise national (1942-1969, president in 1966), member of the commission of inquiry at the time of the business of the Mirage (1964).

Federal adviser (1970-1978, president of the Confederation in 1975), in charge of the political Department, Graber is confronted with delicate files, which it manages with realism: terrorism, hijacking of Zerqa by members of the Liberation popular front of Palestine (September 1970), accession of Switzerland with UNO and relationship with the EEC, universality of the diplomatic relations of Switzerland, development co-operation, creation of the Swiss Body of assistance in the event of catastrophe (auj. Swiss Body of humanitarian aid).

Graber was a brilliant member of Parliament with the caustic irony, broken with the oratorical duels and an effective statesman but with the breakable style. It incarnates the tendency reformist of the socialist party attached to the participation in the Federal council and the democracy of agreement, sometimes in conflict with the left protestor of the party.