Benford received a Bachelor of Science in physics in 1963 from University of Oklahoma in Norman, Oklahoma, followed by a Master of Science from the University of California, San Diego in 1965, and a doctorate there in 1967. That same year he married Joan Abbe. Benford modeled characters in several of his novels after her, most prominently the heroine of Artifact. She died in 2002.

Benford has an identical twin brother, Jim Benford, with whom he has collaborated on science fiction stories. Both got their start in science fiction fandom, with Gregory co-editor of the science fiction fanzine Void. Benford is an atheist.

Gregory Benford's first professional sale was the story "Stand-In" in Magazine of Fantasy and Science Fiction (June 1965). In 1969, he began writing a regular science column for Amazing Stories.

Benford tends to write hard science fiction which incorporates the research he is doing as a practical scientist. He has worked on several collaborations with authors including William Rotsler, David Brin and Gordon Eklund. His time-travel novel Timescape (1980) won both the Nebula Award and the John W. Campbell Memorial Award. A scientific procedural, the novel eventually loaned its title to a line of science fiction published by Pocket Books. In the late 1990s, he wrote Foundation's Fear, one of an authorized sequel trilogy to Isaac Asimov's Foundation series. Other novels published in that period include several near-future science thrillers: Cosm (1998), The Martian Race (1999) and Eater (2000).

Benford has also served as an editor of numerous alternate history anthologies as well as collections of Hugo Award winners.

He has been nominated for four Hugo Awards (for two short stories and two novellas) and 12 Nebula Awards (in all categories). In addition to Timescape, he won the Nebula for the novelette "If the Stars Are Gods" (with Eklund).

Benford was a guest of honour at Aussiecon Three, the 1999 Worldcon. He remains a regular contributor to science fiction fanzines, such as Apparatchik.

In addition to establishing Benford's law of controversy, Benford claims to have created and written about the first computer virus in the late 1960s.

In 2004, Benford proposed that the harmful effects of global warming could be reduced by the construction of a rotating Fresnel lens 1000 kilometres across, floating in space at the Lagrangian point L1. According to Benford, this lens would diffuse the light from the Sun and reduce the solar energy reaching the Earth by approximately 0.5% to 1%. He estimated that this would cost around US$10 billion. His plan has been commented on in a variety of forums. This plan, or a similar one, was proposed in 1989 by J. T. Early, and again in 1997 by Edward Teller, Lowell Wood, and Roderick Hyde. In 2006, Benford pointed out one possible danger in this approach: if this lens were built and global warming were avoided, there would be less incentive to reduce greenhouse gases, and humans might continue to produce too much carbon dioxide until it caused some other environmental catastrophe, such as a chemical change in ocean water that could be disastrous to ocean life.

Benford serves on the board of directors and the steering committee of the Mars Society.

Benford's law of controversy is an adage from the 1980 novel Timescape, stating:

Passion is inversely proportional to the amount of real information available.

The adage was quoted in an international drug policy article in a peer-reviewed social science journal.

Galactic Center Saga

Jupiter Projects

Other series contributions

Man-Kzin Wars (with Larry Niven)

Second Foundation

Non-series novels

Anthologies edited

• Hitler Victorious: Eleven Stories of the German Victory in World War II (1986), with Martin H. Greenberg
• Nuclear War (1988), with Martin H Greenberg
• Far Futures (1995)
• The New Hugo Winners Volume IV (1997), with Martin H. Greenberg
• Nebula Awards Showcase 2000 (2000)
• Microcosms (2004)

Alternate histories

• Alternate Empires (1989) (with Martin H. Greenberg)
• Alternate Heroes (1989)
• Alternate Wars (1991)
• Alternate Americas (1992) (with Martin H. Greenberg)

Non-fiction

• Habitats in Space (1998)
• Deep Time: How Humanity Communicates Across Millennia (1999)
• Skylife: Visions of Our Homes in Space (2000, with George Zebrowsk)
• Skylife: Space Habitats in Story and Science (2000, with George Zebrowski)
• Beyond Human: The New World of Cyborgs and Androids (2001)

Short-story collections

• In Alien Flesh (1986)
• Matter's End (1990)
• Amazing Stories No 7 (1992, with J. R. Dunn, James Alan Gardner and Kim Mohan
• Worlds Vast and various' (1999)
• Immersion and other Short Novels (2002)
• Merlin (2004)

Short stories

• "Stand-In"

The Magazine of Fantasy and Science Fiction (June 1965)

• "Representative From Earth"

The Magazine of Fantasy and Science Fiction (January 1966)

• "Flattop"

The Magazine of Fantasy and Science Fiction (May 1966)

• "Deeper Than the Darkness"

The Magazine of Fantasy and Science Fiction (April 1969)

Sociology Through Science Fiction (1974)

• "Sons of Man"

Amazing Stories (November 1969)

• "Nobody Lives on Burton Street"

Amazing Science Fiction (May 1970)

World's Best Science Fiction (1971)

Sociology Through Science Fiction (1974)

Inside Information (1977)

• " The Scarred Man"

Venture (May 1970)

• "The Prince of New York"

Fantastic (June 1970)

• "3:02 p.m., Oxford"

If (September/October 1970)

• "The Movement"

Fantastic (October 1970)

• "Inalienable Rite"

Quark 1 (1970)

• "But the Secret Sits"

Galaxy Science Fiction (March 1971)

• "Star Crossing", with Donald Franson

If (March/April 1971)

• "Battleground", with Jim Benford

If (May/June 1971)

Guns of Darkness (1987)

• "West Wind, Falling", with Gordon Eklund

Universe 1 (1971)

• "And the Sea Like Mirrors"

Again, Dangerous Visions (1972)

Again, Dangerous Visions, Book 2 (1977)

Masterpieces of Science Fiction (1978)

• "In the Ocean of Night"

Worlds of If Science Fiction (May/Jun 1972)

In the Ocean of Night (1977)

• "Jupiter Project"

Amazing Stories (September 1972)

• "Icarus Descending"

The Magazine of Fantasy and Science Fiction (April 1973)

In the Ocean of Night (1977)

• "Man in a Vice"

Amazing Science Fiction (February 1974)

• "Nobody Lives Around Here"

Vertex: The Magazine of Science Fiction (February 1974)

• "If the Stars Are Gods", with Gordon Eklund

Universe 4 (1974)

Best SF of the Year 4 (1975)

Nebula Award Stories 10 (1975)

The Science Fiction Hall of Fame, Volume IV (1986)

The Science Fiction Century (1997)

• "Threads of Time"

Threads of Time (1974)

In the Ocean of Night (1977)

• Doing Lennon

Analog Science Fiction/Science Fact (April 1975)

Best SF of the Year 5 (1976)

The Arbor House Treasury of Science Fiction Masterpieces (1983)

Light Years and Dark (1984)

In Alien Flesh (1986)

• Beyond Grayworld

Analog Science Fiction/Science Fact (September 1975)

• Cambridge, 1:58 A.M

Epoch (1975)

• John of the Apocalypse

Tomorrow Today (1975)

• White Creatures

New Dimensions 5 (1975)

In Alien Flesh (1986)

• How It All Went

Amazing Stories (March 1976)

100 Great Science Fiction Short Short Stories (1978)

• The Anvil of Jove, with Gordon Eklund

The Magazine of Fantasy and Science Fiction (July 1976)

• Marauder!

Alien Worlds (1976)

• Seascape (aka Pebble Among the Stars)

Faster Than Light (1976)

The Crash of Empire (1989)

• What Did You Do Last Year?, with Gordon Eklund

Universe 6 (1976)

• Hellas is Florida, with Gordon Eklund

The Magazine of Fantasy and Science Fiction (January 1977)

• Homemaker

Cosmos Science Fiction And Fantasy Magazine (May 1977)

• A Snark in the Night

The Magazine of Fantasy and Science Fiction (August 1977)

• Knowing Her

New Dimensions 7 (1977)

Time of Passage (1978)

• Starswarmer

Analog Science Fiction/Science Fact (June 1978)

Analog Science Fiction/Science Fact (September 1978)

• In Alien Flesh

The Magazine of Fantasy and Science Fiction (September 1978)

Best Science Fiction Stories of the Year (1979)

1979 Annual World's Best SF (1979)

Best SF Stories of the Year: Eighth Annual Collection (1979)

The 1979 Annual World's Best SF (1979)

In Alien Flesh (1986)

• Old Woman By the Road

Destinies (November/December 1978)

Thor's Hammer (1979)

The Best of Destinies (1980)

• A Hiss of Dragon, with Marc Laidlaw

Omni, (December 1978)

Best SF of the Year 8 (1979)

Dragon Tales (1982)

The Best of Omni Science Fiction, No. 3 (1982)

• Nooncoming

Universe 8 (1978)

In Alien Flesh (1986)

• Time Guide

Destinies (January/February 1979)

• Dark Sanctuary

Omni (May 1979)

The Endless Frontier (1979)

The Best of Omni Science Fiction, No. 4 (1982)

• Redeemer

Analog Science Fiction/Science Fact (April 1979)

Best Science Fiction Stories of the Year (1979)

Best SF Stories of the Year: Ninth Annual Collection (1980)

The Endless Frontier Vol. II (1982)

In Alien Flesh (1986)

• Calibrations and Exercises

New Dimensions 9 (1979)

The Best of New Dimensions (1979)

• Time Shards

Universe 9 (1979)

Best SF of the Year 9 (1980)

In Alien Flesh (1986)

• Titan Falling

Amazing Stories (August 1980)

• Pick an Orifice

Destinies (Fall 1980)

• Slices

Destinies (Spring 1981)

• Exposures

Isaac Asimov's Science Fiction Magazine (July 1981)

The Road to Science Fiction #4 (1982)

Isaac Asimov's Wonders of the World (Anthology #6) (1982)

Creations: The Quest for Origins in Story and Science (1983)

In Alien Flesh (1986)

Norton Book of SF (1993)

The Ascent of Wonder: The Evolution of Hard SF (1994)

• Shall We Take a Little Walk?

Destinies (Winter 1981)

• Cadenza

New Dimensions 12 (1981)

• Valhalla

The Magazine of Fantasy and Science Fiction (April 1982)

• Lazarus Rising

Isaac Asimov's Science Fiction Magazine (July 1982)

• Relativistic Effects

Perpetual Light (1982)

Best SF of the Year 12 (1983)

In Alien Flesh (1986)

The Ascent of Wonder: The Evolution of Hard SF (1994)

• Sandy Lust

The Berkley Showcase Volume 5 (1982)

• Swarmer, Skimmer

Best SF of the Year 11 (1982)

• The Touch (based on 'Continuidad de los parques', from Final del juego by Julio Cortázar )

The Best of Omni Science Fiction, No. 5 (1983)

R-A-M Random Access Messages of the Computer Age (1984)

• Me/Days

Universe 14 (1984)

In Alien Flesh (1986)

• Time's Rub

Time's Rub (1984)

Isaac Asimov's Science Fiction Magazine (April 1985)

In Alien Flesh (1986)

Mathenauts: Tales of Mathematical Wonder (1987)

Future on Ice (1998)

• To the Storming Gulf

Afterwar (1985)

The Magazine of Fantasy and Science Fiction (April 1985)

In Alien Flesh (1986)

Armageddon! (1989)

• Newton Sleep

The Magazine of Fantasy and Science Fiction (January 1986)

Heroes in Hell (1986)

Nebula Awards 22 (1988)

• Of Space-Time and the River

Isaac Asimov's Science Fiction Magazine (February 1986)

Best SF of the Year 15 (1986)

In Alien Flesh (1986)

• Freezeframe

Interzone (Autumn 1986)

Amazing Stories (May 1987)

Nebula Awards 23 (1989)

• As Big as the Ritz

Interzone, Winter 1986 (1986)

Alien Stars III: Under The Wheel (1987)

• Snatching the Bot

In Alien Flesh (1986)

• Effing the Ineffable

Nebula Awards 21 (1987)

• The Gods of the Gaps

Crusaders in Hell (1987)

• What Are You Going to Be When You Grow Up?

Spaceships & Spells (1987)

• Proselytes

Full Spectrum (1988)

• All the Beer on Mars

Isaac Asimov's Science Fiction Magazine (January 1989)

• Alphas

Amazing Stories (March 1989)

The 1990 Annual World's Best SF (1990)

The Year's Best Science Fiction: Seventh Annual Collection (1990)

• We Could Do Worse

Isaac Asimov's Science Fiction Magazine (April 1989)

What Might Have Been? Vol I: Alternate Empires (1989)

Roads Not Taken: Tales of Alternate History (1998)

• Mozart on Morphine

The Magazine of Fantasy and Science Fiction (October 1989)

• Leviathan

Omni (1989)

• Proserpina's Daughter with Paul A. Carter

Synergy: New Science Fiction, Vol. 3 (1989)

• The Rose and the Scalpel

Time Gate (1989)

Amazing Stories (January 1990)

• Warstory

Isaac Asimov's Science Fiction Magazine (January 1990)

• Latter-Day Matian Chronicles

Omni (July 1990)

• The Eagle and the Cross

Dangerous Interfaces (1990)

• Manassas, Again

Isaac Asimov's Science Fiction Magazine (October 1991)

• Centigrade 233

Isaac Asimov's Science Fiction Magazine (December 1991)

• Touches

Amazing Stories (December 1991)

• Matter's End

Full Spectrum 3 (1991)

The Year's Best Science Fiction: Ninth Annual Collection (1992)

Nebula Awards 28 (1994)

• Down the River Road

Aboriginal Science Fiction' (Summer 1992)

• Rumbling Earth

Aboriginal Science Fiction (Summer 1992)

• World Vast, World Various

Murasaki (1992)

• The Dark Backward

Amazing Stories (February 1993)

More Amazing Stories (1998)

• Doing Alien

The Magazine of Fantasy & Science Fiction (March 1994)

100 Astounding Little Alien Stories (1996)

• The Bigger One

Science Fiction Age (May 1994)

• Soon Comes the Night

Asimov's Science Fiction (August 1994)

• Not of an Age

Weird Tales from Shakespeare (1994)

• Strong Instinct with Mark O. Martin

South From Midnight (1994)

• The Trojan Cat with Mark O. Martin

Man-Kzin Wars VI (1994)

• Deep Eyes

Analog Science Fiction and Fact (April 1995)

• Kollapse

Interzone Science Fiction and Fantasy (April 1995)

Science Fiction Age (May 1995)

• A Worm in the Well

Analog Science Fiction and Fact (November 1995)

Year's Best SF (1996)

• A Tapestry of Thought

Amazing Stories (Winter 1995)

• A Desperate Calculus as Sterling Blake

New Legends (1995)

• High Abyss

New Legends (1995)

• Immersion

Science Fiction Age (March 1996)

The Year's Best Science Fiction: Fourteenth Annual Collection (1997)

• Paris Conquers All with David Brin

The Magazine of Fantasy & Science Fiction (March 1996)

Global Dispatches (1996)

• Afterword: Retrospective with David Brin

Global Dispatches (1996)

• Zoomers

Future Net (1996)

Year's Best SF 2 (1997)

• The Voice

Science Fiction Age (May 1997)

Year's Best SF 3 (1998)

• Galaxia

Science Fiction Age (July 1997)

• A Cold Dry Cradle with Elisabeth Malartrez

Science Fiction Age (November 1997)

The Year's Best Science Fiction: Fifteenth Annual Collection (1998)

• Early Bird

Free Space (1997)

• A Dance to Strange Musics

Science Fiction Age (November 1998)

• Ordinary Aliens

Science Fiction Age (November 1998)

• Three Gods

Interzone (September 2001)

• Menage a Trois

Interzone (November 2001)

• Around the Curve of a Cosmos

Published at scifi.com (2001)

• Brink

Published at scifi.com (2001)

• The Clear Blue Seas of Luna

Asimov's Science Fiction (October/November 2002)

• The Hydrogen Wall

Asimov's Science Fiction (October/November 2003)

Year's Best SF9

• Anomalies
• At the Double Solstice
• A Hunger for the Infinite
• Immortal Night
• Mammoth Dawn with Kevin J. Anderson
• Mandikini
• Side Effect
• Shakers of the Earth
• Sleepstory