Reisz was born in Ostrava, Czechoslovakia of Jewish extraction. He was a refugee, one of the 669 rescued by Sir Nicholas Winton. His father was a Lawyer. He came to England in 1938, speaking almost no English, but eradicated his foreign accent as quickly as possible. After attending Leighton Park School, he joined the Royal Air Force toward the end of the war; his parents died at Auschwitz. Following his war Service, he read Natural Sciences at Emmanuel College, Cambridge, and began to write for film journals, including Sight and Sound. He co-founded Sequence with Lindsay Anderson and Gavin Lambert in 1947.
Reisz was a founder member of the Free Cinema documentary film movement. His first short film Momma Don't Allow (1955), co-directed with Tony Richardson, was included in the first Free Cinema program shown at the National Film Theatre in February 1956. His film We Are the Lambeth Boys (1959) was a naturalistic depiction of the members of a South London boys' club, which was unusual in showing the leisure life of working-class teenagers as it was, with skiffle music and cigarettes, cricket, drawing and discussion groups. The film represented Britain at the Venice Film Festival. The BBC made two follow-up films about the same people and youth club, broadcast in 1985.
His first feature film Saturday Night and Sunday Morning (1960) was based on the social-realism novel by Alan Sillitoe, and used many of the same techniques as his earlier documentaries. In particular, scenes filmed at the Raleigh factory in Nottingham have the look of a documentary, and give the story a vivid sense of verisimilitude. The film won the Grand Award for Best Feature Film at the 1961 Mar del Plata International Film Festival.
Reisz had three sons by his first wife Julia Coppard, whom he later divorced. Reisz wed Betsy Blair, former wife of Gene Kelly, in 1963 and remained married until his death.
The French Lieutenant's Woman (1981) was probably the most successful of his later films. Adapted from the John Fowles novel by Harold Pinter, it starred Jeremy Irons and Meryl Streep. His last films for the cinema were Sweet Dreams (1985), based on the life of country singer Patsy Cline, and Everybody Wins (1990), with a screenplay by Arthur Miller and based on his play. He was a patron of the British Film Institute. His standard textbook The Technique of Film Editing was first published in 1953.
