Thomas Neill Cream was born on May 27, 1850, in Glasgow, Scotland. He was the oldest of eight children in his family. In 1854, his family moved to Canada, where his father became the manager of a shipbuilding and lumber firm. They settled near Quebec City. As a young man, Cream briefly apprenticed in the shipbuilding trade and helped with his father's wholesale lumber business.

In 1872, Cream decided to pursue a career in medicine. He enrolled at McGill University in Montreal, where he studied for four years. While at university, he was known to be extravagant and led a wild lifestyle. He wore flashy clothes and jewelry, and he enjoyed socializing with his peers. Despite his behavior, he graduated with a degree in medicine on March 31, 1876.

After graduation, Cream became involved with Flora Brooks, a young woman from Waterloo, Quebec. When Flora became pregnant, Cream attempted to perform an abortion, which led to her severe illness. Flora’s father caught Cream trying to avoid responsibility and forced him to marry her. However, just a day after the wedding, Cream left Flora and went to England to continue his medical education.

In England, Cream attended St. Thomas's Hospital in London. He completed his postgraduate training there and gained further qualifications as a physician and surgeon in Edinburgh in 1878. Once he finished his studies, he returned to North America and briefly worked in Des Moines, Iowa, before moving to London, Ontario, where he established a medical practice.

Thomas Neill Cream returned to North America in 1878 and started a medical practice in London, Ontario. In 1879, a young woman named Catharine Hutchinson Gardner was found dead behind his office. She was pregnant and had died from chloroform poisoning. Cream had previously refused to help her with an abortion and was later accused of urging her to claim that a local businessman was the father. Despite strong suspicions around him, the case went unsolved.

Cream then moved to Chicago, where he set up a practice near a red-light district. He offered illegal abortions and had multiple patients die after visiting him. In 1881, a woman named Alice Montgomery died after an abortion in a location close to Cream's office, which remained a murder case with no resolution. Another patient, Daniel Stott, died in 1881 after Cream provided him with a supposed remedy for epilepsy that contained strychnine. Stott's death was initially labeled as natural, but after evidence of poisoning was found, Cream was arrested and charged with murder. He was subsequently sentenced to life in Joliet Prison.

In 1891, after being released early from prison, Cream moved to London, England. Soon after, he began murdering again. On October 13, 1891, Ellen Donworth, a sex worker, died from strychnine poisoning after meeting Cream. A week later, he met Matilda Clover, who also died after taking pills he provided.

Cream continued targeting sex workers in London. He attempted to poison Louise Harvey but was unsuccessful. On April 11, 1892, he spent the night with Alice Marsh and Emma Shrivell, both of whom died from poisoning the same night.

Error revealed Cream's involvement with the police noticing his consistent accusations against innocent parties while he wrote blackmail letters. His knowledge about Matilda Clover's death, previously ruled natural, raised alarm. Cream was arrested in June 1892. By July, he was charged with multiple murders and extortion.

At his trial in October 1892, the jury took only 12 minutes to find him guilty. Justice Henry Hawkins sentenced Cream to death by hanging. He was executed at Newgate Prison on November 15, 1892. Reports suggested he claimed to be "Jack" right before he died, though this has been widely disputed. Cream is buried in an unmarked grave in a cemetery.