Seeman was born in 1694 in Gdansk, Poland (known as Danzig in the German language), one of the four sons (all of whom became painters) of Isaac Seeman, a portrait painter. Brought to London by his father when he was young, he was in good practice as a portraitist by 1717, when he painted the full-length of Elihu Yale. Seeman obtained patronage from the Graftons, Pembrokes, Rockinghams, and other aristocratic families, and maintained a respectable position in the second rank of painters in the age that bridged late Kneller and the mature Hudson, but he was never able to command high prices. He painted a number of portrait groups, of which the largest was that of Lady Cust and her nine children. Seeman lived in St. Martin's Lane, and died there in March 1744 or 1745.
[Hayes, John. British Paintings of the Sixteenth through Nineteenth Centuries. The Collections of the National Gallery of Art Systematic Catalogue. Washington, D.C., 1992: 247.]