Born in Bolton, Lancashire, England, Halliwell was captivated by films from an early age. A boy from a modest background, he won a scholarship to Bolton School and after National Service he studied English at St Catharine's College, Cambridge before holding a number of jobs in film journalism and cinema management.

After working for a decade as a researcher and buyer for Southern Television and then Granada Television, in 1968 he took responsibility for purchasing films for the entire ITV network. In 1982, at the personal invitiation of Jeremy Isaacs, he became buyer of U.S. films for Channel 4. He retired in 1986.

Halliwell's tastes were conservative. He had a preference for the cinema of the 1930s and 1940s. In his Film Guide, he gave ratings of 0 stars to 4 stars for films, not giving any film from the 1970s onward a rating of 4 stars as he believed that films needed to be of a certain age before their historical influence could be appraised. Very bad films, subjectively, were not listed by Halliwell: "[I]f only one reader sees merit in an excluded film, it has to be worthy of reconsideration the next time". An average film received 0 stars in Halliwell's system; above average, 1 star. Only very exceptional films received 2 to 4 stars.

John Walker, who took over the editorship after his death, has somewhat broader tastes than Halliwell.

Halliwell's professional knowledge of the entire gamut of cinema is still seen in his encyclopedias The Filmgoer's Companion, now published as Halliwell's Who's Who in the Movies (first published 1965), Halliwell's Film Guide (first published 1977) and Halliwell's Television Companion (first published 1979 as Halliwell's Teleguide).

After his retirement, he wrote for the Daily Mail. He also published a number of historical and critical works about the cinema.

He married Ruth Porter in 1959 and they had one son. Halliwell died of stomach cancer in the Princess Alice hospice in Esher, Surrey.

Halliwell acknowledged his "predecessors" in the 1976 introduction to his 1977 Film Guide:

I salute especially the work of Leonard Maltin, James Robert Parish, Denis Gifford, Douglas Eames and the unsung anonymous heroes who compiled the reviews of the BFI's Monthly Film Bulletin during the fifties and sixties.

This list of Leslie Halliwell's favourite films was originally published in the fifth edition of the Film Guide.

• Citizen Kane (1941)
• Trouble in Paradise (1932)
• The Bride of Frankenstein (1935)
• Le Million (1931)
• A Matter of Life and Death (1946)
• Lost Horizon (1937)
• Sons of the Desert (1933)
• The Philadelphia Story (1940)
• The Maltese Falcon (1941)
• The Lady Vanishes (1938)

Later in 2005, Halliwell's Film Guide declared Yasujir? Ozu's Tokyo Story (1953) as the best film of all time.

The story of the rise and fall of the four-star films can be seen here: [1].

The most idiosyncratic selection is Begone Dull Care, a National Film Board of Canada animated film by Norman McLaren with music by Oscar Peterson.

Works

• 1965. - The Filmgoers' Companion. - ISBN 0002557983
• 1965. - Mountain of Dreams: the Golden Years of Paramount. - ISBN 0246108258
• 1973. - The Filmgoer's Book of Quotes. - ISBN 0583128890
• 1975. - The Clapperboard Book of the Cinema. - ISBN 0246108142 - (with Graham Murray and Granada Television)
• 1977. - Film Guide: A Survey of 8000 English-Language Movies. - ISBN 0007144121 (retitled Halliwell's Film Guide)
• 1979. - Halliwell's Television Companion. - ISBN 0586083790
• 1982. - Halliwell's Hundred. - ISBN 0246113308
• 1985. - Seats in All Parts: Half a Lifetime at the Movies. - ISBN 0246124784
• 1986. - Halliwell's Harvest. - ISBN 0684185180
• 1986. - The Dead that Walk. - ISBN 0804423008
• 1987. - Double Take and Fade Away. - ISBN 0246128356
• 1987. - Return to ShangriLa. - ISBN 0586070818