Henry Benbridge was among the first generation of American artists who received artistic training in Europe. Born to a wealthy family in Philadelphia, Benbridge was able to travel to Italy and London, where he exhibted his work at the Royal Academy. His travels put him in contact with other Americans abroad, such as Benjamin Franklin and the artist Benjamin West. These introductions created opportunities for Benbridge back in the United States, where he later became a fashionable portraitist.

Sarah Boyer was the wife of Robert Shewell, Jr., a young Philadelphia ship master. Her sister-in-law, Elizabeth, was the wife of the leading American expatriate artist Benjamin West. Benbridge had lived with the West family in London, and his portraits of Mr. and Mrs. Shewell are painted with the warmth of family and kinship. The sitter's fashionable outfit indicates that the portrait was painted in the early 1770s, immediately after the artist's return from London.