In his long and prolific career Gilbert Stuart painted only seven full-length portraits (other than those of George Washington). His ambitious and imposing likeness of Captain John Gell (1738–1806) is the second in this series. Stuart executed it in London and there looked to Sir Joshua Reynolds for advice on blending ideal and individual characteristics in grand portraiture. The image epitomizes Stuart's adaptation of Reynolds's manner: The picture is an accomplished combination of fine and apparently slapdash brushwork that conveys an image of heroism and naturalism, duty and sensibility. It suggests spontaneity in execution, belying Stuart's considerable conceptual strategy and technical facility.

In 1785 Gell had just completed his duty on the Monarca, a seventy-gun ship that he had commanded in a series of five naval engagements against the French. He came from a Derbyshire family and was made a lieutenant in the Royal Navy in 1760. Two years later he was promoted to commander, a rank he held for thirty years through active duty in Nova Scotia, the East Indies, Portugal, Toulon, and Genoa, among other places. He advanced to the rank of admiral in 1799.