Mr. Danelius earned his Master of Law degree from Stockholm University in 1955, and was awarded the degree of Doctor of Law honoris causa from the same university in 1988.

He held judicial positions in various courts of the Kingdom of Sweden, before serving as Justice of the Supreme Court of Sweden from 1988 to 2001. His was also a member of the Реrmаnеnt Court of Arbitration in The Hague, a legal officer in the Secretariat of the Еurореаn Commission of Human Rights, and an arbitrator in the OSCE Court of Arbitration and Conciliation and the International Centre for Settlement of Investment Disputes (ICSID).

Mr. Danelius served the Swedish Ministry of Foreign Affairs as Deputy Director of the Legal and Consular Department (1971-75) and Under-Secretary for Legal and Consular Affairs (1975-84, with rank of Ambassador from 1977) and was an Ambassador of Sweden to the Netherlands from 1984 to 1988.

He held several international positions of importance such as Chairman of the Baltic Sea Fisheries Commission, Chairman of the Swedish Delegation to the United Nations Third Conference on the Law of the Sea and a member of the Swedish Delegation to the United Nations General Assembly.

He served as an international Judge of the Constitutional Court of Bosnia and Herzegovina from May 1997 to May 2002.