Avigdor Dagan was born Viktor Fischl to a Jewish family in Hradec Králové, Austria-Hungary (present-day Czech Republic). He studied law and political science at Charles University in Prague, where he lived until the outbreak of World War II. He entered the diplomatic service, and also served as editor of the Jewish weekly Zidovsky Zpravy.
After Nazi Germany invaded his country, he fled to London, where he met the Czech diplomat and politician Jan Masaryk, then serving as Foreign Secretary. With Masaryk, he returned to Prague at the end of the war. When the Communists seized power in 1948, he emigrated to Israel and adopted the Hebrew name Avigdor Dagan.
In Israel he resumed his diplomatic career and was the first Israeli ambassador to Austria 1956; later he was ambassador to Norway and to Poland. At the same time he was writing poetry, short stories, and novels in his native Czech language, and retired in 1977 to devote himself to writing full-time. His best known novel is probably Dvorní šašci (The Court Jesters, 1990). He also wrote for the theater and made modern Czech translations of the Book of Psalms and the Song of Songs.