Tubman was born to Harriet Green and Benjamin Ross in Dorchester County, Maryland in 1820 or 1821. As a baby she was called Araminta, but later changed her name to Harriet after her mother.

Life as a slave was not easy for Tubman. At the age of six she began working as a house servant for people her master hired her out to, and as a teenager she worked in the fields. As many other slaves experienced, she was treated cruelly. Despite hardship, her courage was apparent in her youth. When she was thirteen, she blocked the way of an overseer who was trying to capture a fleeing slave. She was hit in the head with a two-pound weight that was intended for the fugitive slave. Thereafter, she was subjected to sudden sleeping spells.

In 1844, Tubman married John Tubman, a free black. In 1849, after her master's estate had been broken up, she feared that she would be sold. She told her husband that she planned to escape, but he threatened to turn her in. After she learned that she had in fact been sold to a Georgia slave trader, she secretly devised a plan without her husband's knowledge. On the night of her escape, she traveled to Bucktown, where she sought the assistance of a white woman. She had met the woman on several occasions while working in the fields. The woman had offered her assistance, so Tubman took a chance that she was sincere. When she arrived at the woman's house, she was told of two places she could safely stop. Tubman traveled through the woods and the next morning she reached the first stop where a woman fed her, then gave her a broom and told her to sweep out front so that it would look like she belonged there. That night the woman's husband loaded his wagon with produce and Tubman lay under a blanket with it. They traveled for several hours to the next destination where she was instructed to follow the river to the next stop. She followed the river to a station where she was rowed up the Choptank River. As she traveled on, she was hidden on a Quaker farm, in a haystack on a farm belonging to German immigrants, and for a week in a potato hole in a cabin belonging to free blacks. By the time she reached Pennsylvania, she had traveled 90 miles to freedom.

For two years, Tubman lived in Philadelphia, where she worked as a hotel cook. It was there that she met William Still, the secretary of the Philadelphia Vigilance Committee. This group was founded by a group of blacks and it helped fugitive slaves avoid capture. She visited the Vigilance Committee frequently and learned about the Underground Railroad network.

It was not long after her introduction to the Vigilance Committee that she became a conductor for the Underground Railroad. After hearing that her sister and her sister's children were going to be sold, she volunteered to help them escape. Regardless of William Still's warnings about the dangers she might face because she was a fugitive slave, she helped her sister and family travel from Cambridge, Maryland to Philadelphia.

This was just the start of her role as a conductor. In 1851, she helped her brother escape along with two other men. She continued into the late 1850s to conduct fugitives to safety. She made two trips a year, one in the spring and one in the fall. In between trips, she worked to fund them. The destination of her trips changed when the Fugitive Slave Act of 1850 took effect. The act required Northern states to return escaped slaves, so it became dangerous for fugitives to settle in the North. Instead, Tubman made sure that each party she conducted made it safely to Canada. She also made sure that her parents made it to Canada. In 1857, she dreamed that her parents were going to be sold. Despite their age, she was able to help them make it to Canada and later bought them a house in Auburn, New York.

By 1858, Tubman had led over 300 fugitive slaves to freedom. By this time she had become known for her work on the Underground Railroad, and a $40,000 reward was offered for her capture. She also became known for her lectures. In 1858, after her first speech at an anti-slavery meeting, the audience became intrigued by her stories about her life as a conductor. Influenced by the demand for her to devote her time to the anti-slavery lecture circuit, she stopped making trips to the South. But in 1860 Tubman grew tired of the lecture circuit and made her last trip as an Underground Railroad conductor. On this trip, she led a party of six to Philadelphia.

During the Civil War, Tubman served as a nurse and spy for Union soldiers. After the war, she cared for her parents in Auburn, New York. She also spent her time helping former slaves. She raised money to pay for the education of ex-slaves, for children's clothing, and for schools. In 1869, she married Nelson Davis, a former slave and Union Army soldier. Later in her life, she devoted her time to women's suffrage. She died in 1913.