Turtledove was born in Los Angeles, California, and grew up in nearby Gardena. His parents, Romanian immigrants, first settled in Winnipeg, Canada, before making their permanent home on the US West Coast. After dropping out during his freshman year at Caltech, he attended UCLA, where he received a Ph.D. in Byzantine history in 1977. His dissertation was entitled The Immediate Successors of Justinian: A Study of the Persia Problem and of Continuity and Change in Internal Secular Affairs in the Later Roman Empire During the Reigns of Justin II and Tiberius II Constantine (AD 565—582).

In 1979, Turtledove published his first two novels, Wereblood and Werenight, under the pseudonym "Eric G. Iverson." Turtledove later explained that his editor at Belmont Tower did not think people would believe the author's real name was "Turtledove" and came up with something more Nordic. He continued to use the "Iverson" name until 1985, when he published his "Herbig-Haro" and "And So to Bed" under his real name. Another early pseudonym was "Mark Gordian." Turtledove has recently begun publishing historical novels under the pseudonym "H.N. Turteltaub" (Turteltaube means turtle dove in German). He published three books as Dan Chernenko (the Scepter of Mercy series).

Throughout the late 1970s and early 1980s, Turtledove worked as a technical writer for the Los Angeles County Office of Education. In 1991, he left the LACOE and turned to writing full time. From 1986 to 1987, he served as the Treasurer for the Science Fiction Writers of America.

He has written several works in collaboration, including The Two Georges with Richard Dreyfuss, "Death in Vesunna" with his first wife Elaine O'Byrne, Household Gods with Judith Tarr, and others with Susan Shwartz, S.M. Stirling and Kevin R. Sandes.

Turtledove won the Homer Award for Short Story in 1990 for "Designated Hitter," the John Esten Cooke Award for Southern Fiction in 1993 for The Guns of the South, the Hugo Award for Novella in 1994 for "Down in the Bottomlands." "Must and Shall" was nominated for the 1996 Hugo Award for Best Novelette, the 1996 Nebula Award for Best Novelette and received an honorable mention for the 1995 Sidewise Award for Alternate History. The Two Georges also received an honorable mention for the 1995 Sidewise Award for Alternate History. The Worldwar series received a Sidewise Award for Alternate History Honorable Mention in 1996. In 1998, the novel How Few Remain won the Sidewise Award for Alternate History. He won his second Sidewise Award in 2003 for the novel Ruled Britannia. On August 1, 1998, Turtledove was named honorary Kentucky Colonel while Guest of Honor at Rivercon XXIII in Louisville, Kentucky. The Gladiator was the co-winner of the 2008 Prometheus Award.

Turtledove served as the toastmaster for Chicon 2000, the 58th World Science Fiction Convention.

He is married to mystery and SF writer Laura Frankos. His brother-in-law is fantasy author Steven Frankos. He has three daughters: Alison, Rachel and Rebecca.

Turtledove has been dubbed "The Master of Alternate History". Within that genre he is known both for creating original alternate history scenarios such as survival of the Byzantine Empire or an alien invasion in the middle of the Second World War and for giving a fresh and original treatment to themes previously dealt with by many others, such as the victory of the South in the American Civil War and of Nazi Germany in the Second World War. His novels have been credited with bringing alternate history into the mainstream. His style of alternate history has a strong military theme with scenes of combat happening throughout many of his works.

Elabon

• Wereblood (1979) ... using Eric Iverson pseudonym
• Werenight (1979) ... using Eric Iverson pseudonym
• Werenight (revised edition, 1994)
• Prince of the North (1994)
• Wisdom of the Fox (1999, collects the revised Werenight and Prince of the North)
• King of the North (1996)
• Fox and Empire (1998)
• Tale of the Fox (2000, collects King of the North and Fox and Empire)

The Videssos Books

Fantasy series about a world that is analogous to the Byzantine Empire.

• The Videssos cycle
• The Misplaced Legion: One of Julius Caesar's legions is transported to a world with magic. (1987)
• An Emperor for the Legion (1987)
• The Legion of Videssos (1987)
• The Swords of the Legion (1987)
• The Tale of Krispos Series
• Krispos Rising (1991)
• Krispos of Videssos (1991)
• Krispos the Emperor (1994)
• The Time of Troubles Series
• The Stolen Throne (1995)
• Hammer and Anvil (1996)
• The Thousand Cities (1997)
• Videssos Besieged (1998)
• The Bridge of the Separator (2005)

Worldwar & Colonization Series

Science Fiction/Alternate History ... Aliens invade in the middle of World War II

• Worldwar Tetralogy
• In the Balance (1994)
• Tilting the Balance (1995)
• Upsetting the Balance (1996)
• Striking the Balance (1996)
• Colonization Trilogy
• Second Contact (1999)
• Down to Earth (2000)
• Aftershocks (2001)
• Homeward Bound (2004)

The Southern Victory or Timeline-191 Series

Alternate History ... The South has won the American Civil War; this posits what would then happen over the next century. (The series consists of several smaller series and has no official title)

• How Few Remain (1997)
• The Great War Trilogy
• American Front (1998)
• Walk in Hell (1999)
• Breakthroughs (2000)
• The American Empire Trilogy
• Blood and Iron (2001)
• The Center Cannot Hold (2002)
• The Victorious Opposition (2003)
• The Settling Accounts Tetralogy
• Return Engagement (2004)
• Drive to the East (2005)
• The Grapple (2006)
• In at the Death (2007)

Darkness Series

A fantasy series about a world war between nations using magic as weapons. Many of the plot elements are analogous to elements of World War II, with countries and technologies that are comparable to the events of the real world, while the writing style is similar to Timeline-191.

• Into the Darkness (1999)
• Darkness Descending (2000)
• Through the Darkness (2001)
• Rulers of the Darkness (2002)
• Jaws of the Darkness (2003)
• Out of the Darkness (2004)

War Between the Provinces Series

A reversed fantasy version of the American Civil War, set in a world where magic significantly works. The industrial-magical south is fighting the rural north over the blond serfs.

• Sentry Peak (2000)
• Marching Through Peachtree (2001)
• Advance and Retreat (2002)

Hellenic Traders Series

A historical fiction series about two cousins who are traveling merchants in the fourth century BC Mediterranean. The novels were written under the H.N. Turteltaub pseudonym.

• Over the Wine Dark Sea (2001)
• The Gryphon's Skull (2002)
• The Sacred Land (2003)
• Owls to Athens (2004)

Crosstime Traffic Series

This series is based on the premise that travel between parallel universes is possible. This is a series for young adults. Turtledove makes sure not to use any profanity or racial slurs in this series.

• Gunpowder Empire (2003)
• Curious Notions (2004)
• In High Places (2006)
• The Disunited States of America (2006)
• The Gladiator (2007)
• The Valley-Westside War (2008)

Days of Infamy series

In the Days of Infamy series the Japanese gained the initiative in the Pacific War by invading and occupying Hawaii.

• Days of Infamy (2004)
• End of the Beginning (2005)

The Atlantis Series

A trilogy of books which describes a world where the American eastern coast from the tip of Florida to Nova Scotia breaks away from the mainland millions of years in the past and has an island biota similar to New Zealand's. Discovered in 1452 and named Atlantis, this eighth continent becomes a focal point in a gradually diverging timeline. Two short stories, "Audubon in Atlantis" and "The Scarlet Band" have been set in this milieu.

• Opening Atlantis (2007)
• The United States of Atlantis (2008)
• Liberating Atlantis (2009)
• Atlantis and Other Stories (2010) - Collects Audubon in Atlantis" and "The Scarlet Band".

Opening Atlantis was nominated for the 2009 Prometheus Award.

Opening of the World

A trilogy of books describing a fantasy world in which inhabitants of an Iron Age empire explore a land uncovered by a receding glacier

• Beyond the Gap (2007)
• Breath of God (2008)
• The Golden Shrine (2009)

The War That Came Early

A series describing an alternate World War II which begins in 1938 over Czechoslovakia. The number of volumes has not been set. The first volume, Hitler's War, was released in hardcover in 2009 without a series title. Subsequently, the paperback edition was announced as The War That Came Early: Hitler's War. As of this writing, six total volumes have been contracted for.

• Hitler's War (2009); to be published in paperback as The War That Came Early: Hitler's War (2010).
• The War That Came Early: West and East (2010)
• The War That Came Early: The Big Switch (no date announced)
• Volume IV
• Volume V
• Volume VI

Stand-alone Books

• The Chronicle of Theophanes, Harry Turtledove editor and translator, University of Pennsylvania Press, 1982. A translation of an important Byzantine historical text, completed soon after Harry Turtledove's PhD studies.
• Agent of Byzantium (1987) ... Imperial Byzantine special agent Basil Argyros is sent on various missions in an alternate universe where Muhammad became a Christian saint and consequently the Byzantine Empire never fell.
• A Different Flesh (1988) ... a related set of short stories spanning the 17th to 20th centuries set in a universe where the ancestors of the Native Americans never crossed into the New World, only Homo erectus.
• Noninterference (1988) ... A human interstellar survey team violates a directive to avoid interference with alien civilizations, with disastrous long-term consequences.
• Kaleidoscope (1990) ... short story collection
• A World Of Difference (1990) ... In this alternative history story, the 4th planet of our solar system is larger and named Minerva instead of Mars. The Viking space probe of the 1970s sends back one picture ... that of an alien creature swinging a stick ... before losing contact. A USA mission and a USSR mission are sent to explore the planet; these two missions start separately but later have to cooperate.
• Earthgrip (1991)
• The Guns of the South (1992) Science Fiction/Alternate History ... The Confederate Army is supplied with AK-47's by time travelling members of the Afrikaner Weerstandsbeweging from the early 21st century.
• The Case of the Toxic Spell Dump (1993) ... EPA agent David Fisher battles displaced magical powers in a very creative sorcerous equivalent to late-20th century Los Angeles. He follows the evidence to a toxic spell dump, where dangerous remnants of industrial sorcery are stored.
• Departures (1993) ... short story collection
• Down in the Bottomlands (1993) ... At the end of the Miocene period, the Mediterranean Sea stays dry to the present day. The dry sea basin is a large canyon containing a national park, and the hero must race to stop villains from letting in the Atlantic and flooding the area.
• The Two Georges (1995) Alternate History/Mystery, co-authored with Richard Dreyfuss ... Set in the year 1996 of an alternate timeline where the American Revolution was peacefully avoided. The painting that symbolizes the union between North America and Britain is stolen by terrorists, and officers of the Royal North American Mounted Police must find it before it is destroyed.
• Thessalonica (1997) ... Early Christians in the Greek city of Thessalonica deal with barbarian invaders on both a physical and metaphysical level.
• Between the Rivers (1998) ... Taking place in an equivalent to ancient Mesopotamia, city-states ruled by different gods fight for dominance.
• Justinian (1998) ... Fictionalized account (with some speculation involved) of the life of the Byzantine Emperor Justinian II...using H.N. Turteltaub pseudonym
• Household Gods (1999) ... co-written with Judith Tarr Science Fiction/Alternate History ... A modern lawyer finds herself in the Roman Empire of Marcus Aurelius.
• Counting Up, Counting Down (2002) ... short story collection
• The Daimon (2002) - A novella included in the alternate history collection Worlds That Weren't. It describes a world where the Greek philosopher Socrates aids the Athenian general Alkibiades in defeating the Spartans, allowing him to unite the city-states of ancient Greece and contemplate war on the Persian Empire.
• Ruled Britannia (2002) Alternate History ... The Spanish Armada conquers England and forces Shakespeare to write a play about Philip II. At the same time he is secretly writing a play for the English underground resistance about Boudica's rebellion, with Boudica meant to be analogous to the imprisoned Elizabeth I.
• In the Presence of Mine Enemies (2003) Alternate History ... Follows the struggles of a family of secret Jews in Berlin two or three generations after a Nazi victory in World War II. The events in the story follow a common theme of Turtledove's work, transplanting one set of historical events into another setting (the most prominent example being Timeline-191 moving European history onto the American continent). In this case, the decline of the Soviet Union in the 1990s is translated to the Third Reich in the 21st century (and the secret Jews' way of life is reminiscent of Marranos in Spain).
• Conan of Venarium (2004) a tale set in the youth of Robert E. Howard's Conan the Barbarian.
• Every Inch a King (ISFiC Press) (2005) An acrobat becomes king of a small country. Although set in a fantasy world, it is analogous to the real world, this time in the Balkans, between the first and second Balkan War. Shqiperi is modeled on Albania, and the story itself is modeled on the story of Otto Witte.
• Fort Pillow (2006) - Historical retelling of the Battle of Fort Pillow.
• The Man with the Iron Heart (2008) - Reinhard Heydrich survives an assassination in Czechoslovakia by partisans and later goes on to lead an insurgent movement against the allied occupation of Germany. This is another historical transplant, in this case the Iraqi insurgency of 2003 is transplanted to postwar Germany.
• After the Downfall (2008) - A Wehrmacht officer is transported into a fantasy world during the Russian invasion of Germany at the end of World War II.
• Reincarnations (2009) - A limited edition hardcover containing eight stories, including six never before reprinted and one original story.
• Give Me Back My Legions! (2009) - A historical novel detailing the events leading up to the Battle of the Teutoburg Forest, as well as the battle itself.

Web Publishing

• Winter of Our Discontent: The Impeachment and Trial of John F. Kennedy (2007) - Co-written with TV series creator Bryce Zabel. After John Kennedy survives the attack at Dealey Plaza unharmed, the resulting investigation sets events in motion that tear apart his administration. (First three chapters only, plus commentary)