Born in New York City, Sharon Kay Penman grew up in New Jersey. She received her bachelor's degree from the University of Texas at Austin, where she majored in history. She also received a Juris Doctor degree from Rutgers University School of Law, and later worked as a tax lawyer.

As a student, Penman researched and wrote the manuscript of the historical novel The Sunne in Splendour that chronicled the life of Richard III. She believed Richard III was unfairly treated by historians so decided to write about his life which became The Sunne in Splendour. When the 400-page manuscript was stolen from her car, Penman found herself unable to write for the next five years. Eventually Penman rewrote the story and by the end spent twelve years on the book while simultaneously practicing law. Of practicing law, she admits she "considered it penance."

Penman lives in New Jersey, and in the early 1980s moved to Wales to research her second book, Here Be Dragons. She keeps a second home in the Welsh mountains where the history inspires her and provides material for her novels.

Penman's first novel The Sunne in Splendour (1982) is 936 pages long and presents the final act in England's War of the Roses. King Richard III is characterized as a healthy, albeit misunderstood ruler. After conducting research, both in the United States and in the United Kingdom, Penman found herself believing that "his was a classic case of history being rewritten by the victor."

Once finished with The Sunne in Splendour she became "hopelessly hooked" on writing. She knew there was plenty of material to be written about the "rebellious sons and disgruntled brothers and conniving kings and willful queens" of the Plantagenets and hoped to write as many as a dozen books. After the publication of The Sunne in Splenour, Penman began work on the Welsh Trilogy, primarily set in Wales. The "Welsh Trilogy" was followed by the "Henry II Trilogy" that revolves around events during the life of King Henry II and Eleanor of Aquitaine.

Penman decided to keep the settings of her books in the Middle Ages, but the next series was set earlier than The Sunne in Splendour, in the 13th century. She wrote a trilogy about the collision of political power in medieval England and Wales. During her research for Here Be Dragons she found the role of women in medieval society to be more complex than is often expected; she learned that Welsh women enjoyed a great deal of independence in relation to their English counterparts. Whether in Wales or in England, a noble wife had responsibility for a household, complete with household knights, whom the wife relied upon to keep the household safe.

In 1996 Penman published the first in the series of four medieval mystery novels. Penman's first mystery, The Queen's Man, the first of the Justin de Quincy series, was a finalist for an Edgar Award for Best First Mystery from the Mystery Writers of America. Penman explains her reasons for turning to the mystery genre after writing only historical novels: "By the time I'd finished researching and writing When Christ and His Saints Slept, I was in danger of burning out. For the first time in nearly two decades, my boundless enthusiasm for the Middle Ages had begun to flag. So I decided I needed a change of pace, and since I am a long-time mystery fan, it occurred to me that a medieval mystery might be fun to write. Once that idea took root, it was probably inevitable that I'd choose to write about Eleanor of Aquitaine, surely one of history's most memorable women."

Set in the 12th century, Penman presents the young Justin de Quincy as medieval sleuth in of the series. In the first book he is elevated to the status of "queen's man" by Eleanor of Aquitaine. The Queen's Man and Cruel as the Grave depicts the period after King Henry II's death, as Eleanor, about age 70, rules the Angevin empire with one son in captivity, and another son (John) hovering at the edge of power. The third novel in the series, The Dragon's Lair, is set during the same period, but Penman shifts the locale to northwest England and north Wales. And finally in the last novel of the series, Prince of Darkness, Penman continues to show the conflict between mother and sons, and weaves in de Quincy's conflicts as well.

In addition to the Edgar Award, Penman is the winner of the 2001 Career Achievement Award for Historical Mysteries from Romantic Times.

Here Be Dragons (1985) is the first of Penman's series of novels about the medieval princes of Gwynedd. Of the novel, Penman states, “I think Dragons is so popular because it was virgin territory for most readers. The saga of the Plantagenets was much better known, but not many people were familiar with medieval Wales or its princes. And then, too, the story of Llewelyn the Great and Joanna, King John’s illegitimate daughter, is a remarkable one, which struck an emotional chord with many readers.”

In Falls the Shadow (1988) Penman chronicles the family relationships of King Henry III and his brother-in-law Simon de Montfort. Falls the Shadow can be considered a "bridge novel" as Penman uses the Simon de Montfort rebellion to lead her to the conclusion of the trilogy in The Reckoning. As Penman explains: '“After I’d finished Here Be Dragons, I knew I wanted to continue the story....At first I’d planned to write one book in which Simon de Montfort would share top billing with Llewelyn Fawr’s grandson, Llewelyn ap Gruffydd, who later wed Simon’s daughter. I soon realized, though, that this was too much to tackle in one book, that Simon and Llewelyn each deserved his own novel. So I decided to devote Falls the Shadow to Simon and The Reckoning to Llewelyn".

Penman's characterization of Simon de Montfort is that of a man increasingly disillusioned by his sovereign and who rebels in 1263, becomes regent to Henry III, and attempts to reestablish rights granted under the Magna Carta. In addition to the story of Simon de Montfort and his wife, Eleanor the Countess of Pembroke and sister to King Henry III, the novel presents characters such as the Welsh ruler Llywelyn Fawr and London's FitzThomas.

Of her research for Falls the Shadow, Penman explains: "I did a great deal of on-site research, visiting the castles and battlefields that figured in Falls the Shadow, visiting the Reading Room at the British Library, the National Library of Wales in Aberystwyth, and local reference libraries....Here at home, I made use of the University of Pennsylvania Library in Philadelphia, which has an excellent medieval selection. But it really helped to see the scenes for myself. At Lewes, we actually walked along the same path that Simon de Montfort and his men would have followed. It was breathtaking to stand on the Downs, gazing out upon the same view that he would have seen".

The Reckoning (1991) chronicles the reign of England's King Henry III in Penman's final volume of the series that began with Here Be Dragons. The conflict between the Welsh prince Llewelyn ap Gruffydd who is the grandson of Llewelyn the Great of Here Be Dragons, and England's King Henry III is one subplot. Additionally, Penman chronicles the life and character of Ellen, daughter of Simon to Montfort's and niece to Henry III; her betrothal to Llewellyn (negotiated prior to de Montfort's death); and the conflict between Ellen and her cousin Edward, soon to become King Edward, who opposes the betrothal.

In the Plantagenet trilogy Penman chronicles Angevin kings, beginning with King Henry II's childhood in "When Christ and His Saints Slept." Of Henry II and his wife Eleanor of Aquitaine, Penman explains:

Henry II and Eleanor of Aquitaine were larger than life, legends in their own lifetimes. He was one of the greatest of the medieval kings, and she was the only woman to wear the crowns of both England and France. They loved and fought and schemed on a stage that stretched from the Scots border to the Mediterranean Sea. Their children were branded by contemporaries as "The Devil’s Brood," but they founded a dynasty that was to rule England for three hundred years.

My first novel in their trilogy, When Christ and His Saints Slept, traces the beginning of their tempestuous union. Time and Chance continues their story at high noon. From the greenwoods of Wales to a bloodied floor at Canterbury Cathedral, theirs was an amazing story, and I very much enjoyed being along for the ride!

When Christ and His Saints Slept (1995) is the first of the Plantagenet trilogy. When Christ and His Saints Slept introduces the genesis of the Plantagenet dynasty as Queen Maude battles to secure her claim to the English throne. In 15 years she wrote three novels and four mysteries set during the period of Henry II and Eleanor of Aquitaine. Penman found no villains in "this cast of characters". Instead she focused on the human characteristics: Henry II was a "brilliant king" but a "bad father". Eleanor of Aquitaine was a "law unto herself". Penman found the role of the medieval woman intriguing...particularly that of a medieval queen.

Time and Chance (2002) is about King Henry II, Eleanor of Aquitaine, and the rift between Henry II and Thomas à Becket. It became a New York Times bestseller. Time and Chance spans a 15-year period from 1156 to 1171 as King Henry II becomes estranged from his wife (although Eleanor and Henry have eight children during eight years), and from his close friend and advisor Thomas a Becket. King Henry's decision to elevate Becket to the Archbishop of Canterbury becomes a fulcrum for discord between Henry and Eleanor.

The Devil's Brood (2008) is the final volume in the Plantagenet trilogy. The Devil's Brood concludes the story Henry II and Eleanor of Aquitaine. The Devil's Brood opens with the conflict between Henry II, his wife Eleanor of Aquitaine, and their four sons, which escalates into a decade of warfare and rebellion pitting the sons against the father and the brothers against each other while the mother spends the period imprisoned by her husband. Once again Penman places the characters against a tightly woven rich tapestry of medieval life, personal conflict, and dramatic characters.

Penman's approach to her novels is to present meticulously researched medieval life and history as everyday life; and to present the nobility as fallible. Set against a backdrop of political tension, power struggles, war, and hardship, the main characters confront personal drama such as conflict in love, conflict between family members, conflict between one's God, and conflict in friendship, as well as conflicted loyalties between family, self, king and country. A Library Journal review praises Penman's attention to detail in which she "combines an in-depth knowledge of medieval Europe with vivid storytelling, re-creating the complex events and emotional drama of the 12th century."

Although set in the 12th and 13th centuries, Penman sets the characters and narrative in her novels in medieval sites that still exist and can be visited, including castles, churches and archeological areas. Areas such as Aber Falls and Dolwyddelan Castle have important scenes in Penman's novels. In Devil's Brood, Penman sets the characters in scenes in a variety of medieval royal residences, castles and abbeys, in England and present day France, many of which still exist such as the Château de Chinon, Fontevrault Abbey, and Chateau de Loches.

• The Sunne in Splendour New York : Holt, Rinehart, and Winston, c1982 ISBN 0-03-061368-X London: Macmillan, 1983, c1982 ISBN 0-333-34463-4
• Here Be Dragons New York : Holt, Rinehart, and Winston, c1985 ISBN 0-03-062773-7 London: Collins, 1986 ISBN 0-00-222960-9
• Falls the Shadow New York : H. Holt, c1988 ISBN 0-8050-0300-2 London: Joseph, 1988 ISBN 0-7181-2923-7
• The Reckoning New York : H. Holt, 1991 ISBN 0-8050-1014-9 London: Joseph, 1991 ISBN 0-7181-2948-2
• When Christ and His Saints Slept New York : H. Holt, 1995 ISBN 0-8050-1015-7 London: Joseph, 1994 ISBN 0-7181-3585-7

• The Queen's Man New York : H. Holt, 1996 ISBN 0-8050-1015-7 London: Joseph, 1996 ISBN 0-7181-3981-X
• Cruel as the Grave New York : Henry Holt, 1998 ISBN 0-8050-5608-4 London: Joseph, 1998 ISBN 0-7181-4307-8
• Time and Chance New York : Putnam’s, c2002 ISBN 0-399-14785-3( London: Joseph, 2002 ISBN 0-7181-4308-6
• Dragon's Lair New York : G.P. Putnam’s Sons, c2003 ISBN 0-399-15077-3 London: Penguin, 2005 ISBN 0-14-025098-0 (pbk.)
• Prince of Darkness New York : G.P. Putnam’s Sons, c2005 ISBN 0-399-15256-3
• Devil's Brood New York : G. P. Putnam’s Sons, c2008 ISBN 978-0-399-15526-0 London: Joseph, 2009 ISBN 0-7181-5465-7