Robert Holdstock, the oldest of five children, was born in Hythe, Kent. His father, Robert Frank Holdstock, was a police officer and his mother, Kathleen Madeline Holdstock, was a nurse. At the age of seven years, Robert started attending the Gillingham Grammar School in the Medway Towns. As a young adult he had jobs including banana boatman, construction worker, and slate miner.

As an adult he earned a Bachelor of Science from University College of North Wales, Bangor, with honours in applied Zoology (1967–1970). He continued his education, earning a Master of Science in Medical Zoology at the London School of Hygiene & Tropical Medicine in 1971. He conducted research at the Medical Research Council in London from 1971 to 1974 while also doing part-time writing. He became a full-time writer during 1976 and lived out the rest of his life in North London.

He died in hospital at the age of 61, following his collapse with an E. coli infection on 18 November 2009."Locus Roundtable: Robert Holdstock." Locus Online: The Website of The Magazine of the Science Fiction & Fantasy Field. Web. 29 Nov. 2009. .

Robert Holdstock's first published story, Pauper's Plot, appeared in the New Worlds magazine in 1968. His first novel was a science fiction work titled Eye Among the Blind, released in 1976.

During the late 1970s and throughout the 1980s Holdstock wrote many fantasy and science fiction novels along with a number of short stories, most of which were published under a pseudonym. Robert Holdstock's pseudonyms include Robert Faulcon, Chris Carlsen, Richard Kirk, Robert Black, Ken Blake, and Steven Eisler.

In 1980 Holdstock cowrote Tour of the Universe with Malcolm Edwards. The rights were subsequently sold for a space shuttle simulation ride at the CN Tower, also called the Tour of the Universe.

Holdstock wrote a novella, The Dark Wheel, which was included with the best-selling 1984 computer game Elite. Holdstock has also written The Emerald Forest, based on the film of the same name as directed by John Boorman (director of Deliverance and Excalibur amongst others). He also novelised episodes of the Granada television seris Bulman.

Holdstock's breakthrough novel Mythago Wood was published during 1984 with his true name. Mythago Wood is recognized as Holdstock's first major fantasy work and begins the Ryhope wood series. The books in this series started with the Mythago Wood novella published in 1981 and continue to the present day with the sequel to Mythago Wood, Avilion, published in July 2009.

From 2001 to 2007 Holdstock produced a trilogy of fantasy novels, the Merlin Codex, consisting of Celtika, The Iron Grail and The Broken Kings.

Holdstock has authored, edited, and contributed to a number of non-fiction works including Alien Landscapes, Tour of the Universe, Horror: 100 Best Novels and the Encyclopedia of Science Fiction (not The Encyclopedia of Science Fiction.)

Holdstock's works have been subject to much literary analysis. The majority of this analysis is of Mythago Wood.

David Pringle describes Eye Among the Blind, Holdstock's first science fiction novel, as a "dogged, detailed, somewhat slow-moving planetary mystery." Regarding the same novel Ursula K. Le Guin remarked "As strong a treatment of a central theme of science fiction – alienness, and the relation of the human and the alien – as any I have read."

According to Michael D. C. Drout, a modern J. R. R. Tolkien scholar, Holdstock's fantasy is a significant part of the fantasy literature genre. This is because (in the Ryhope wood series) Holdstock has created literary arts containing the power and aesthetic standards of Tolkien’s fantasy without being either a "close imitation of" or a "reaction against" Tolkien. Drout considers Holdstock, along with Ursula K. Le Guin, a worthy inheritor of the fantasy tradition created by Tolkien. According to a study of Tolkien's works by Partrick Curry, Holdstock is placed in a quartet of noteworthy fantasy authors including Ursula K. Le Guin, John Crowley and Marion Zimmer Bradley for writing fantasy books that come close to Tolkien's breadth and depth of imagination, and "in some respects surpass Tolkien."

One essayist states "Robert Holdstock's gift for evoking landscapes and weaving mythic patterns is outstanding." Accordingly, the covers of his books have been produced by a variety of notable Science Fiction and Fantasy illustrators. The original UK and US covers of Mythago Wood were illustrated by Eddi Gornall and Christopher Zacharow, respectively; Geoff Taylor illustrated the original UK covers for the Mythago Wood sequels Lavondyss, The Bone Forest, The Hollowing and Merlin's Wood. Illustrators of subsequent covers and editions include Jim Burns, Tom Canty, John Howe, Alan Lee, John Jude Pallencar, Larry Rostant, and Ron Walotsky. John Howe stated "Holdstock is to me one of the best Celtic fantasy authors alive today."

David Langford offers praise for most of Holdstock's work, but regarding Merlin's Wood he states "the overall narrative is flawed, distorted by its weight of undeserved loss and inaccessible healing."

Ryhope Wood series

• Mythago Wood
• Lavondyss
• The Bone Forest, a novella and short story collection
• The Hollowing
• Merlin's Wood, a novel and two short stories (only published in the UK)
• Gate of Ivory, Gate of Horn
• Avilion

Merlin Codex series

• Celtika
• The Iron Grail
• The Broken Kings

Other novels

• Eye Among the Blind
• Earthwind
• Necromancer
• Where Time Winds Blow
• In the Valley of the Statues (short story collection)
• The Emerald Forest (film novelisation)
• The Fetch (also published under the title Unknown Regions)
• Ancient Echoes