Kennealy-Morrison was born in Brooklyn, New York and reared in on Long Island in the hamlet of North Babylon.

She attended St. Bonaventure University for two years, majoring in Journalism. She later transferred to Harpur College (now Binghamton University) where she graduated with a B.A. in English Literature in 1967. She then moved to New York City, where she worked first as a lexicographer for Macmillan Publishing, then as an editorial assistant at and, from 1968—1971, editor-in-chief of Jazz and Pop magazine. She was one of the first female rock critics, leaving the field in 1971.

As editor-in-chief of Jazz and Pop she first interviewed Jim Morrison of the rock band The Doors in January 1969. After the interview, they began a correspondence, became friends and later lovers. She and Morrison exchanged marriage vows in a Celtic Pagan handfasting ceremony in June 1970. Before witnesses, one of them a Presbyterian minister, the couple signed a document declaring themselves wed. Although handfasting, like other religious ceremonies, is not legal unless the appropriate State paperwork is filed, she later changed her legal name to include Morrison's name, and Morrison addressed letters and poems to her as "Patricia Morrison" and "my wife, Patricia". Jim Morrison's will, however, left everything to his long-time companion Pamela Courson. In the will, Jim writes: "I am an unmarried person".

In 1992, Kennealy-Morrison published a memoir about her years with Jim Morrison, Strange Days: My Life With And Without Jim Morrison. She also discusses their relationship in an interview in the book Rock Wives. She served as an advisor on Oliver Stone's movie The Doors, and played a small role in the film as the High Priestess who marries the Jim and Patricia characters (portrayed by Val Kilmer and Kathleen Quinlan). However, in subsequent interviews and writings she was scathingly critical of Stone's portrayal of Morrison, herself, and other people who were the basis for the film's fictional characters, saying Stone's fiction bore little to no resemblance to the people she had known or the events they lived through; Stone admitted that the character named after her was a composite of several of Morrison's girlfriends and regretted not giving her a fictional name. In the film her character is referred to as a "Wicca Priestess", but Kennealy-Morrison identifies as a Celtic Pagan, not a Wiccan.

In 2000, Robin Ventura, third baseman for the pennant-winning New York Mets, took the phrase "Mojo Risin" from The Doors' "L.A. Woman" and made it the rallying cry for the team that year. Ventura and the Mets invited Kennealy-Morrison to a game just before the playoffs, where she met with them and became a Mets fan.

Unfortunately for Mets fans, the Celtic Pagan spell cast by Kennealy-Morrison upon the New York Yankees did not work during that year's World Series, as the Mets succumbed to the Yankees four games to one in the 2000 Fall Classic.

On May 19, 2007, Kennealy-Morrison announced via her blog that she will be starting her own publishing house, Lizard Queen Press, and self-publishing more novels and non-fiction. The next Keltiad novel will be The Beltane Queen, and another memoir is in the works, as well.

In June 2007 the author posted that she was in the midst of final preparations to publish Ungrateful Dead: Murder at the Fillmore, the first in a series of murder mysteries set in the turbulent world of Sixties rock & roll. Ungrateful Dead introduces the character of Rennie Stride, rock reporter/detective, and her boyfriend (later husband) Turk Wayland, superstar English lead guitarist. Kennealy-Morrison has described the series as:

Seamlessly blending the fictional with the real: the stars, the bands, the music, all the excitement of the most incredible decade of the last century... Full of rockworld dish and attitude, created by someone who was not only there for it but made some of it happen herself, and who took just enough drugs to get into it and not so many that she can't remember it...

Ungrateful Dead was published on November 1, 2007, to coincide with both the Day of the Dead and The Celtic New Year.

The author's legal name is "Patricia Kennealy Morrison". As a rock critic and editor, she published under her birth name, "Patricia Kennely", and later as "Patricia Kennealy". From 1994 - 2007 her books were published as "Patricia Kennealy-Morrison", with the hyphen. Ungrateful Dead is her first book to be published as simply "Patricia Morrison".

Novels

The Keltiad

• Blackmantle: A Triumph (1997)

Tales of Aeron

• The Copper Crown (1984)
• The Throne of Scone (1986)
• The Silver Branch (1988)

Tales of Arthur

• The Hawk's Grey Feather (1990)
• The Oak Above the Kings (1994)
• The Hedge of Mist (1996)

Colloquies of the Ancients

• The Deer's Cry (1998)

The Rennie Stride Mysteries

The Rock & Roll Murders

• Ungrateful Dead: Murder at the Fillmore (2007)
• California Screamin': Murder at Monterey Pop (2009)

Non-fiction

• Strange Days: My Life With And Without Jim Morrison (1992)

Anthologies

• Rock She Wrote: Women Write About Rock, Pop, and Rap, eds Evelyn McDonnell and Ann Powers (1995), "Rock Around the Cock". ISBN 0-385-31250-4
• The Faces of Fantasy: Photographs by Patti Perret, intro Terri Windling, ISBN 0-312-86182-6
• Crusade of Fire: Mystical Tales of the Knights Templar, ed Katherine Kurtz (2002), "The Last Voyage". ISBN 0-446-61090-9