At 24, he signed his name to Charter 77, the declaration written in 1977 that called on the government to respect human rights. He was a member of the music bands such as Psí vojáci, Narodní třída, and Načeva, for which he wrote lyrics. His first novel Sister has transformed him from an underground star into an internationally-acclaimed cult author. For his latest novel, A Sensitive Man, Jáchym has been awarded the State Prize for Literature. His books have been translated into more than ten languages, including German, English, and Spanish.
As a signatory to Charter 77, he worked in the 1980s as a warehouseman, fireman or coal carrier, and belonged to the Czech underground. He printed secret flyers, transcribed "undesirable" literature, or smuggled the books of forbidden Czech authors, such as Václav Havel and Milan Kundera, across the border. In 1985 he was one of the founders of the Revolver Revue magazine – a magazine for new literature. After 1990 he worked for Respekt, later for Lidové noviny.
In his latest novel A Sensitive Man Jáchym continues his unique line of poetics: he deals with serious historical themes, concentrates on the lower social classes of the human community, and uses a language rich in expressions.