Belle Starr was born Myra Maybelle Shirley on her father's farm near Carthage, Missouri, on February 5, 1848. Most of her family members called her May.

Her mother, Elizabeth "Eliza" Hatfield Shirley, was a distant relative to the Hatfields of the famous Hatfield-McCoy family feud.

In 1866 the James-Younger Gang robbed their first bank in Liberty, Missouri, and fled with $6,000 in cash and bonds. Splitting up, Jesse James and his brother Frank, along with the Youngers, fled to Texas, where they met up with Belle, a childhood friend from Missouri. According to some reports, Belle was smitten by Cole Younger and quickly became an unofficial member of their gang.

She married Jim Reed in 1866, after having had a crush on him as a teen. It is believed that Belle accompanied Jim on many of his criminal pursuits dressed as a man, and in 1874, a warrant was issued for her arrest in connection with a stagecoach robbery.

Belle left Jim when she discovered his affair with another woman named Rosa McCommas. Jim continued his criminal career until he was shot dead by a lawman named John Morris in 1874.

In 1880, she married a Cherokee man named Sam Starr and settled with the Starr family in the Indian Territory. There, she organized, planned, and fenced for rustlers, horse thieves and bootleggers. She also harbored them from the law. Belle's illegal enterprises proved lucrative enough that she was able to employ bribery to free her colleagues from jail whenever they were caught.

Bass Reeves, the first black deputy U.S. marshal west of the Mississippi River, arrested more than 3,000 dangerous criminals during his legendary law enforcement career, including Belle and Sam Starr. The couple was charged with horse theft and tried before "The Hanging Judge" Isaac Parker in Fort Smith, Arkansas. Belle was found guilty and served nine months at the Detroit House of Corrections in Detroit, Michigan. She proved to be a model prisoner and won the respect of the prison matron. In contrast, Sam was incorrigible and assigned to hard labor.

She received a classical education and learned piano, while graduating from Missouri's Carthage Female Academy, a private institution that her father had helped to found.

On December 17, 1886, Sam Starr was involved in a gunfight with his cousin--deputy marshal Frank West. Both men were killed, and Belle's life as an outlaw queen--and what had been the happiest relationship of her life--abruptly ended with her husband's death.

In order to keep her residence on Indian land, she married a relative of Sam Starr, Jim July Starr, who was some 15 years younger than she was. She decided that outlaws were no longer welcome at her farm. If she thought this would be the end of her troubles, she would be proven tragically wrong.