Born and raised in Prague he began studying at the Academy of Musical Art in Prague in 1960 where he began writing film scripts, and radio plays for Czech public radio - Český rozhlas. Until 1968 he worked as a producer for Czech puppeteer Jiří Trnka. In the same year, Sidon's first book, "Sen o mém otci" ("Dream about my father") was published, in which the author deals with his being brought up without his Jewish father Alexander Sidon, who perished in the Terezín ghetto (his wife was a Christian). In 1977 he was a signatory to Charter 77. He received the Jiří Kolář prize in 1978.
In 1983 he emigrated to West Germany and converted to Judaism after studying Jewish studies at the Heidelberg university. He became ordained as a Rabbi after studying for a time in Israel. He returned to the Czech Republic in 1992, where he became chief rabbi of Prague. He was married to Marcela Třebická, and a father of the actors Daniel Sidon and Magdalena Sidonová.
In Prague in 2005 tensions developed between Chabad members and its rabbi Rabbi Manis Barash and Efraim Sidon. The Old New Synagogue in Prague's ancient Jewish Quarter became the scene of an emotional dispute between members of the Chabad movement and locals backing Karol Sidon, chief rabbi of the Czech Republic. The conflict led to violent brawls and hospitalisations on a number of occasions. Sidon was eventually returned to his post.
In 2004 Tomáš Jelínek, the director of the community council, fired Sidon as Rabbi of Prague giving the post to young Chabad rabbi Manis Barash. A grassroots campaign from community members led to the deposition of Jelinek as the community director. Jelinek then asked a religious arbiter in Israel to rule on the case who ruled in favor of Rabbi Barash. Sidon's supporters argued that the case was void since Jelinek had lied to the Judge telling him that the community board had been behind his actions in firing Sidon and appointing Barash. However on 21 November 2005 he was reelected as the chief Rabbi of the city following the protracted dispute with Chabad. Deputy chairman of the community Jakub Roth told the press: "this is part of the local Chabad’s striving to take over the community’s religious life. We have seen an ugly foray of Chabad in their attempt to take over the Old-New synagogue."
- Sen o mém otci, 1968, (Dream about My Father)
- Sen o mně, 1970, (Dream about Myself)
- Boží osten, 1975, (The Sting of God)
- Brány mrazu, 1977, (Gates of Frost)
- Dvě povídky o utopencích, 1988, (Two Stories about the Drowned People)
- Gospel podle Josefa Flavia, 1974, (The Gospel According to Josephus Flavius)
- Zákon, 1968, (The Law)
- Labyrint (cirkus podle Komenského), 1972, (Labyrinth, Circus According to Comenius)
- Shapira, 1972, (Shapira)
- Zpívej mi na cestu, (Sing Me for the Trip)
- Maringotka Zuzany Kočové, (Caravan of Zuzana Kočová)
- Pohádky ze čtyř šuplíčků, 1979, (Fairy Tales from Four Drawers) (appeared under the name of his wife Marcela Třebická).
- Bohemia Docta aneb Labyrint světa a lusthauz srdce (2000) (Bohemia Docta or Labyrinth of the World and Lusthauz of the Hearh)
- Adam a Gabriel (1973) (Adam and Gabriel)
- Dovidenia v pekle priatelia (1970) (Goodbye in Hell Friends)
- Ptáčkové, sirotci a blázni (1969) (Birds, Orphants and Fools)
- Zběhové a poutníci (1968) (Deserters and Pilgrims)
- Jewish conflict turns violent: Community, Chabad vie to control Prague's Old-New Synagogue, Dinah A. Spritzer, The Prague Post, April 21, 2005
- Stoking controversy, Sidon is reappointed as Prague chief rabbi, Spritzer, Dinah A, Jewish Telegraphic Agency, December 9, 2005
|Wikimedia Commons has media related to Karol Sidon.|
- Literature by and about Karol Sidon in the German National Library catalogue Literature by Karol Sidon in the catalog of the German National Library (German)