[1] As an elected politician Kleppe served in the position of deputy representative to the Norwegian Parliament from Oslo during the term 1954–1957.

[2] From 1962 Kleppe was assigned full time secretary of Den finanspolitiske komité, and from 1963 to 1967 he was subdirector at EFTA in Geneva, and from 1967 to 1971 he headed Arbeiderbevegelsens utredningskontor ("The Labour movement's Research Office").

[3] As Minister of trade Kleppe was given the task to finish the negotiations of Norwegian membership of the European Economic Community (EEC).

The so-called "Kleppe package [no]", where the State contributed by offering improvements of certain benefits during salary negotiations between employer and employee organisations, came to be a central element to minimize inflation.

In order to inhibit the threatening increase of unemployment, the government introduced several supportive measures and economic guarantees to the industry, in particular to maritime transport and shipyards.

[2] In 1981 Kleppe took over as general secretary of the European Free Trade Association,[2] succeeding Swiss Charles Müller [de].

[2] He wrote the books Norges vei til Europa (1989) and Visjonen og hverdagen (1990), and finally his memoirs/autobiography, Kleppepakke, which was released in 2003.