He was named Baruh Djaki Karyo at birth in 1953 in Istanbul, Turkey; his mother was Greek and his Father was from a Sephardic Jewish family with ancestral roots in Spain. When he was young, his family moved to Paris, France, where he grew up. The spelling of his name, Djaki, was changed to Tchéky in a form of French transliteration. As a young man, Karyo studied drama at the Cyrano Theatre and later became a member of the Daniel Sorano Company, playing many classical roles.

Karyo joined the National Theatre of Strasbourg, where he starred in both contemporary and classical plays. He found success in French films beginning in the 1980s, first as a character actor. He later appeared in leading roles in several notable films, such as The Bear, in which he played one of the Hunters, and Director Luc Besson's Nikita, in which he played the heroine's spy mentor.

He was nominated for a César Award for Most Promising Actor for his role in La Balance. In 1986, he was awarded the Jean Gabin Prize in recognition of his acting performances.

He has participated in many Hollywood movies, often portraying a French character, in the same fashion as Jean Reno. He has acted in prominent roles in major films set during wartime. Such performances include his acting as a vengeful French officer alongside Mel Gibson in The Patriot (2000), set during the American Revolutionary War, and his role as Jean de Dunois in The Messenger: The Story of Joan of Arc. In the DVD edition of The Patriot, Karyo overdubbed his own lines on the French-language track.

Karyo is also a musician and Songwriter. He released the highly acclaimed 2006 album Ce lien qui nous unit (translated in English as "the link that binds us"), and released Credo in 2013 on his 60th birthday.

In 2014 and 2016 Karyo has received critical praise for his performance as Julien Baptiste in the acclaim BBC One/Starz drama series The Missing.