Fuks was born in Prague on September 24, 1923, the son of Vaclav Fuks (a police officer) and Marie Frycková Fuksová. He studied the Gymnasium in Truhlářšká ulice, where he also first witnessed Nazi persecution of his Jewish friends. In 1942 he was forced to be a caretaker in Hodonín, as a part of the Arbeitseinsatz.
Later he studied philosophy, psychology and art history at the Philosophical faculty of Charles University in Prague, where, in 1949, he received a doctorate. After his studies, he was a member of the National heritage administration and after 1959 he worked in the national gallery. He became a professional writer in the 1960s. He attracted much attention with his debut work, ''Pan Theodor Mundstock'' (''Mr. Theodore Mundstock''), published in 1963, and a year later with his short story collection ''Mí černovlasí bratři'' (''My dark-haired brothers'').
During the communist period, Fuks said he "preferred to choose conciliatoriness and toleration over reckless defiance and courage to fall in the resistance" (). Some of his work from the 1970s is strongly linked to the era in which it was created; for example, ''Návrat z žitného pole'' (The Return from the Rye Field) is a novel targeted against emigration after the 1948 communist coup. He was also a member of the socialist Union of Czech Writers (). Although he obtained some international recognition, in the last years of his life he was left alone and friendless. He died in 1994 in his Prague apartment in the Dejvice neighborhood, at ''Národní obrany'' no. 15.
