The son of a maker of carriage bodies, James Frothingham was born near Boston, in Charlestown, Massachusetts, in 1786. Initially he worked in his father's shop, where he taught himself to paint the finished coaches. He also experimented in sketching and is said to have received some instruction from Fabius Whiting, a younger artist based in Lancaster. Frothingham began his training by painting portraits of family members; by about age 20 he had abandoned the carriage-making trade for full-time portrait work. During this early stage of his career he visited Gilbert Stuart, who was to have a profound influence on his later development. Although unimpressed by Frothingham's first efforts, Stuart eventually revised his opinion and encouraged the younger artist with periodic criticism of his portraits. Frothingham became one of several artists to adopt Stuart's light-toned, freely brushed manner, and he often executed copies of his mentor's likenesses.

After working for more than a decade in Boston and Salem, he moved with his wife and three children to New York City in 1826. Soon he began exhibiting at the Boston Athenaeum (despite his recent move) and the National Academy of Design. The latter institution elected him an associate member in 1828 and a full academician in 1831. He served as its corresponding secretary in 1844. Frothingham was particularly active during the 1830s, but his production fell off at about age 60. He spent the last two decades of his life in Brooklyn, where he died in 1864. His daughter Sarah became a painter of miniatures. [This is an edited version of the artist's biography published, or to be published, in the NGA Systematic Catalogue]