Benjamin West was born on October 10, 1738, in Springfield–then Chester County, now Delaware County–Pennsylvania, to Sarah (Pearson) and John West. According to his memoir, West’s fascination with art began at a young age. His first drawing was of his baby niece, Sally, which he drew while caring for her. After seeing the portrait, his parents encouraged him to pursue his talent for drawing and painting. West’s earliest paintings were all portraits, first of children and then of other residents near Lancaster, Pennsylvania.

West’s early works attracted some attention. Edward Pennington, a merchant from Philadelphia and a family friend, was so impressed that he gifted the boy with new paints and took him to Philadelphia to paint in the city. One of his early subjects was a gunsmith named William Henry. Henry allegedly encouraged West to transition from portraits to historical paintings.

After his trip to Philadelphia and at the urging of Henry, West started focusing on historical subjects, which he would eventually be known for. He painted his first historical work, The Death of Socrates, in 1756. It is based on an engraving by Hubert Gravelot in the fourth volume of Charles Rollins' Ancient History. After seeing West’s work, William Smith, the first Provost of what is now the University of Pennsylvania, invited him to study classical art, literature, and history in Philadelphia. West was never listed as an enrolled student because Smith created a unique curriculum for him that emphasized history and art.

Besides his education with Smith, West received tutoring from several other sources while living in Philadelphia. These include William Williams, an English artist, and John Valentine Heidt, a German artist. In 1760, Smith arranged for West to sail to Italy to continue his arts education.

West spent three years living and painting in Rome, Florence, and Venice. At first, his work showed Renaissance and Neo-classical influences but later he evolved toward Romanticism. He worked closely with Anton Raphael Mengs, a German artist, who taught him in Rome and sent him to northern Italy to study art collections. After spending time in Italy, West settled in London in 1763. In September 1764, he married Elizabeth Shewell, a daughter of a Philadelphia merchant. They had two sons, Raphael Lamar West (born in 1766, and Benjamin West, Jr. (born in 1772).

During this period West painted The Continence of Scipio (1766) and Pylades and Orestes (1766), both of which were exhibited at the Spring Gardens in Charing-Cross by the Society of Artists of Great Britain. Continence of Scipio illustrates the Roman general Scipio Africanus, nobly returning a captured Carthaginian maiden back to her family. Pylades and Orestes (1766) is based on a play by the classical author Euripides. The two semi-naked men have been arrested for trying to steal a gold statue of Diana from the temple. Iphigenia, a priestess of Diana, has brought them to be sacrificed on the altar. In the painting, West focused on the dramatic moment when Iphigenia recognizes the man in the red drapery as her brother, Orestes.

Two years later, Robert Hay Drummond, Archbishop of York, commissioned West for Agrippina Landing at Brundisium with the Ashes of Germanicus (1768).  It depicts the widowed Agrippina returning to Rome carrying the ashes of her assassinated husband, Germanicus. This piece caught King George III’s attention and led to the monarch’s patronage of West. He appointed West a member of the Royal Academy of Arts in London in 1769.

A year after his appointment to the Academy, West painted the Death of General Wolfe. The painting depicts the general’s demise during the Siege of Quebec in the French and Indian War. At a time when heroic figures were conventionally portrayed in Greco-Roman styles, Wolfe and his men were shown on the Plains of Abraham in contemporary clothes. West’s choice of realistic attire was a controversial one, but he enabled viewers to feel even more connected and engaged with a monumental moment that led to a British victory.

West’s role as a painter for King George III grew. In 1772, he finished one of his most famous historical works, William Penn's Treaty with the Indians, which portrayed William Penn and his men outdoors, offering gifts to Native Americans. In the same year, the King appointed West as his official historical painter. In addition to illustrating religious, classical, and historical subjects, he continued to portray royal family members. He painted upwards of sixty paintings for George III.

When the first president of the Royal Academy, Joshua Reynolds, passed away in 1792, West became the academy’s second president, serving from 1792 to 1805 and re-elected in 1806. He continued to be involved with the Royal Academy, where he attended lectures and other programs, even after his tenure as president.

By the end of his life, West’s portfolio included over 400 oil paintings. His most notable legacy was his training of other American artists. His students included William Pratt, Charles Willson Peale, and Charles Robert Leslie. Peale, arguably his most famous student, became known for large portraits of George Washington and other Revolutionary War figures. By the end of his career, West was also known for his complex compositions and a glazing technique that was new to American art. The spread of his techniques from London to the United States created a distinct and sophisticated style during the Federal period. West’s work has hung in various museums including the Metropolitan Museum of Art (New York), the National Gallery of Art (Washington, D.C.), and the Philadelphia Museum of Art.

West’s wife, Elizabeth, died in 1814. He passed away on March 11, 1820, at the age of 82 and he is buried in St. Paul’s Cathedral in London.