Jane Toppan was born as Honora Kelley on March 31, 1854, in Boston, Massachusetts, to Irish immigrant parents. Tragically, her mother, Bridget Kelley, died of tuberculosis when Jane was very young. Her father, Peter Kelley, was known for his erratic and abusive behavior, which earned him the nickname "Kelley the Crack" among locals. His mental health deteriorated severely, and it was rumored that he once sewed his own eyelids shut while working as a tailor.

In 1860, just a few years after his wife's death, Peter was unable to care for his family and surrendered his two youngest daughters, eight-year-old Delia Josephine and six-year-old Honora, to the Boston Female Asylum, an orphanage for needy girls. He never reunited with them. 

The orphanage records noted that the girls were "rescued from a very miserable home." While there, it was reported that Delia later turned to prostitution, and their older sister Nellie was committed to an insane asylum.

Less than two years after being left at the orphanage, in November 1862, Honora was placed as an indentured servant with the Toppan family in Lowell, Massachusetts. Although the Toppans never formally adopted her, Honora took their surname, becoming Jane Toppan, as a way to leave her past behind. In the Toppan home, she formed a good relationship with their biological daughter, Elizabeth, and began to forge a new life under her new name.

In 1885, Jane Toppan began her nursing training at Cambridge Hospital, where she quickly gained a reputation as a cheerful and competent nurse, affectionately nicknamed "Jolly Jane." However, beneath her pleasant facade, Jane harbored dark intentions. She became overly familiar with her patients, particularly targeting those who were elderly and gravely ill, and used them to conduct horrifying experiments with morphine and atropine. She manipulated their medication dosages to observe the effects on their nervous systems, even falsifying medical charts and lying beside them as they drifted in and out of consciousness.

Jane's alarming practices at Cambridge eventually led to her recommendation to Massachusetts General Hospital in 1889, where her career continued briefly before she was dismissed for improperly administering opiates. Undeterred, she found work as a private nurse, thriving in her role despite occasional accusations of theft. By 1895, Jane's sinister activities escalated into a full-blown poisoning spree, beginning with her landlord and his wife. Her most chilling series of crimes occurred in 1901 after she moved in with the Davis family in Cataumet to care for the elderly Alden Davis following his wife's death—who was also a victim of Jane's. In a matter of weeks, she poisoned Mr. Davis, his sister Edna, and his two daughters, Minnie and Genevieve.

Suspicion arose when the Davis family ordered a toxicology report on Minnie, confirming she had been poisoned. Jane was soon under surveillance by the police and was arrested in late October 1901. By the following year, she had confessed to thirty-one murders, although she insisted on her sanity during the trial, claiming an awareness of her actions and their wrongfulness. Nonetheless, she was declared insane and sentenced to life in the Taunton Insane Hospital, where she died in 1938.

Jane Toppan's case was notorious not only for the number of her victims but for the perverse satisfaction she reportedly derived from their suffering. Her actions fit the pattern of an "angel of mercy" killer, using her position as a caretaker to exploit the most vulnerable. Beyond her murders, Jane also manipulated those around her for personal gain, even poisoning herself to garner sympathy from potential suitors.