Born Jan P. Isbell, the daughter of John Miller Isbell and Georgia Bonner Isbell, she later changed her name to Isbelle.
She reportedly encouraged her mother and sister to spell the family name Isbelle, and they sometimes complied, sometimes not, although there has been found only one old document in Colonial Virginia in which her ancestor Zachary Isbell was recorded as Isbelle. The original family name in Medieval England was Fitz-Isbell.

Elizabeth Reaser played the character based on her but renamed "P.J. Lane" in the 2013 Lifetime/A&E television mini-series "Bonnie and Clyde."

She was a staff writer for the Dallas Morning News and author of hundreds of newspaper features, articles and columns, several books, and numerous magazine articles, short stories and poems published under the byline Jan Isbell, Jan Isbell Fortune, Jan Isbelle Fortune, Jan I. Fortune, and Jan Fortune. All her earlier articles were published as Jan Isbell.

Her father, Judge John Miller Isbell, was the son of Jason Isbell (1808-1857) and Permelia Ann Watters Isbell. Jan's grandfather was said to be the son of Jason Isbell Sr. (1756-1816), son of Capt. Zachariah Isbell who fought the British at the Battle of King's Mountain during the Revolutionary War.

Jan's father John Miller Isbell was the first judge of Collingsworth County, Texas, but was the sheriff of Harris County at the time of his death. He was killed in the line of duty at Laporte, shot through the heart by a bandit. At the time of his death, Sheriff Isbell carried in his breast pocket a photo of his first child. That childhood photo, punctured by bullet holes and stained with blood, was kept by the child in the photo, Jan Isbell Fortune, and preserved by her for the rest of her life until she finally gave it to her sister Lucile Isbell Stall. It is now in possession of Lucile's great-great-grandson, Terry Hunter Jr.

Jan P. Isbell married Dec. 17, 1910 (or April 9, 1912 per one source) Joseph Byrd Fortune, Jr. (12 Dec 1888 - 17 Dec 1974) and had four children (Wellington Leader, July 23, 1970). One died young. They separated by 1940, divorced after 1942 but before April 1948. Joseph Byrd Fortune was her cousin, being the son of Joseph Bird Fortune Sr., son of James Fortune Sr. and Caroline Watters Fortune.

Jan Isbell Fortune married her second husband, Justin Marble Stone, 31 Dec 1940 at Tevate, Mexico. She is listed as Jan Isbell Fortune Stone in the Catalog of Copyright Entries, Third Series, 1948. He was 26 years her junior, the son of Oliver Raymond Stone and Ruth Esther (Marble) Stone; born 1 Jul 1918, Furnas Co., Nebraska, died 9 Mar 1959, Los Angeles, California. Justin Stone's brother Clarke R. Stone married Jan's daughter, Jarvis Ann Fortune, on Dec. 5, 1942. Both brothers were in the U.S. Navy during World War II.
In 1940 Justin was 22 years old and Jan Fortune Stone age 48.

Jan Isbell Fortune was the mother of three children who lived to adulthood:
Joseph Byrd Fortune III (15 Jan 1913 - Jan. 26, 1958) who suffered hydrocephalus from birth and though he completed three years of high school, he lived with his father, maternal grandmother and stepmother most of his life and never married.

Jan graduated from Wellington (Texas) High School with the Class of 1910.

Jan Isbell Fortune II (1917-1954) who married first, July 15, 1932, L.E. Adler Jr. and later divorced; married secondly, Sept 27, 1935, Dallas, Tx., Edward V. Goodin (7 March 1908 Ky - 17 September 1987).

Jarvis Ann Fortune (born 30 Mar 1925) married 5 Dec 1942, Oakland, Calif., Clarke Raymond Stone, son of Oliver Raymond Stone and Ruth Esther (Marble) Stone. He became the author of Decentralization and Decision Making: An Analysis of the Perceptions of High School Principals and Central Office Administrators (1973). Clarke Stone's brother Justin married Clarke's mother-in-law, so Clarke's wife Jarvis Ann became her own mother's sister-in-law.
He m.2 (1950) Jean Neff b.1930; div. Dec 1974;
m.3 (22 May 1976) Emma J. Willie (b.1936);
m.4 Betty Greathouse, daughter of Virgil Y. Greathouse and Frances Jo (Thrash) Greathouse.

As a reporter for the Dallas Evening Journal, and previously the Morning News, Jan I. Fortune wrote numerous articles on Depression-era bandits Bonnie and Clyde. Winning the friendship of the Parker and Barrow families, she secured some information inaccessible to other reporters and even published two of Bonnie Parker's biographical poems for the first time. For more than a year she worked on interviews with the mothers of both as well as Clyde's sister before the couple was ambushed and killed by officers on May 25, 1934. In September 1934, just three months after the ambus, her book "FUGITIVES: The Story of Clyde Barrow and Bonnie Parker" was published and became an instant bestseller. Admissions made in the publication helped convict 20 Barrow and Parker relatives of harboring the fugitives from justice and netted an array of prison sentences, some as much as two years, and included 30-day jail sentences for both mothers. Two years later, Jan Fortune left Texas and became a screenwriter in Hollywood.

Jan. I. Fortune, Author:
BLACK POPPIES (1922, 1929) by Jan Isbelle Fortune
FUGITIVES: THE TRUE STORY OF CLYDE BARROW AND BONNIE PARKER (1934); as told by the Mother of Bonnie and the Sister of Clyde; compiled, edited, & arranged by Jan I. Fortune; retitled:
THE TRUE STORY OF BONNIE AND CLYDE (1968) by Emma Parker, Nell Barrow Cowan, Jan I. Fortune
TOWER TO THE EAST: A Sonnet Sequence (1934) by Jan Isbelle Fortune
TEXAS HISTORY PLAYS (1936) by Jan Isbelle Fortune
CAVALCADE OF TEXAS (1936) by Jan Isbell Fortune and Clinton Bolton
THE CAVALCADE OF THE CAVALIERS (Richmond, 1938) by Jan Isbelle Fortune for the Richmond Bicentennial
MISS ABBIE'S HONOR (1948) by Jan Isbelle Fortune
ELISABET NEY (1943) by Jan Isbell Fortune and Jean Burton
CAVALCADE OF THE AMERICAS by Jan Isbelle Fortune (Mar. 30, 1937) Greater Texas and Pan American Exposition, Dallas

Jan Fortune, Screenwriter: (Partial)
1939 Man of Conquest starring Joan Fontaine
1939 The Real Glory (cowriter) starring Gary Cooper
1940 Dark Command, starring John Wayne
1942 Mokey, screenplay by Wells Root and Jan Fortune (starring Bobby Blake)
1942 The Vanishing Virginian, starring Kathryn Grayson
1943 The Youngest Profession (contributing writer - uncredited) (starring Lana Turner, Greer Garson, and also featuring Jane Isbell)
1951 Anne of the Indies (cowriter, original script), starring Jean Peters, Louis Jourdan, Debra Paget

In "The Youngest Profession" (1943), Jan Isbell Fortune's distant cousin Jane Isbell (1927-1994) played the role of "Jane."

"Cynthia Parker," an opera by Julia A. Smith about Quannah Parker's mother, was adapted from Jan I. Fortune's Cavalcade of Texas. It was originally to be presented at the Texas Centinniel 1936-37 but was not completed in time. It was produced at the Dallas Little Theater with a rewritten libretto by Hatcher Hughes, playwriting professor at Columbia University (courtesy of Betsy Deiterman, Polk County Memorial Museum).

Lineage:
1 John Isbell (England to Gloucester Co,, Virginia by 1664), presumptive father of
2 William Isbell of Isbell Spring, ss Mattaponi, St. John's Parish, King William County; father of William Jr., Henry (& John?)
3 Henry Isbell b.c1690 of Orange Co.; constable of Caroline Co., d. c1760
+ daughter of "James Cox, Gent.," d c1739 St. Mark's Parish, Orange Co. (July 25, 1733; Spots Orders, 7 Aug, p.240)*
4 Hon. Zachariah Isbell c1722-86 *[1,2,3]
+ (1) Catherine (2) Eliz. (Miller?) *[4]
5 Jason Isbell 1756-1816 Warren Co, TN
+ Polly, d. Jackson Co, AL *[5]
6 Jason Isbell 1808-1857
+ Permelia Ann Watters
7 Hon. John Miller Isbell 1851-1899
+ Georgia Anna Bonner *[6]
8 Jan Isbell Fortune

*1 Colonial Dames of the 17th Century
2 First Families of Tennessee
3 Daughters of the American Revolution & SAR
4 Some say Eliz., dau of John & Hannah Miller (First Families of Kentucky)
5 First Families of Alabama
6 Daughters of the Republic of Texas & SRT

Her granddaughter stated she believed she was buried by her husband at Forest Lawn. She was cremated.