Van Eekelen attended a Gymnasium in Utrecht from June 1943 until June 1949 and applied at the Utrecht University in June 1949 majoring in Law and obtaining a Bachelor of Laws degree in July 1951. Van Eekelen attended Princeton University and graduated in 1952 with an A.B. in politics after completing a senior thesis titled "The Marshall Plan and Its Significance for the Netherlands."[2] Van Eekelen graduated with an Master of Laws degree from the University of Utrecht in November 1954. Van Eekelen was conscripted in the Royal Netherlands Army serving in the cavalry Regiment Huzaren van Boreel as a Lieutenant from July 1956 until August 1957. Van Eekelen worked as a civil servant for the Ministry of Foreign Affairs from September 1957 until June 1977 for the Diplomatic service from September 1957 until May 1974 as an Attaché in New Delhi, India from September 1957 until January 1960 in London, England from January 1960 until February 1964. Van Eekelen later returned to the Utrecht University in February 1964 for another postgraduate education where he worked as a researcher and got an doctorate as an Doctor of Philosophy in Political science on 18 November 1964.
Van Eekelen worked as Attaché in Accra, Ghana from November 1964 until October 1966 and as a senior attaché for the Permanent Representative of the Netherlands to the European Union from October 1966 until May 1971 and as a Consul for the European Economic Community from May 1971 until August 1974. Van Eekelen worked as Director-General for the department of Atlantic Cooperation and Security Affairs of the Ministry of Foreign Affairs from August 1974 until June 1977.
Van Eekelen remained active in national politics, in April 1989 he was nominated as Secretary General of the Western European Union, serving from 15 May 1989 until 15 November 1994. Van Eekelen was elected as a Member of the Senate after the Senate election of 1995, taking office on 13 June 1995 serving as a frontbencher chairing several [parliamentary committees. In January 2003 Van Eekelen announced his retirement from national politics and that he wouldn't stand for the Senate election of 2003 and continued to serve until the end of the parliamentary term on 10 June 2003.
Van Eekelen is known for his abilities as a negotiator and consensus builder. Van Eekelen continues to comment on political affairs as of 2024 and holds the distinction as the only Dutchman that served as Secretary General of the Western European Union.[4]