Here are some clues:
1. This artist was admired by Isabella Stewart Gardner.
2. He painted her portrait which hangs in the Isabella Stewart Gardner museum in Boston.
3. Although he was born in Italy and spent time painting in Venice, he is considered an American artist.
4. His sisters donated this graphite drawing on off-white wove paper in 1931 to the Harvard Fogg Art Museum in Cambridge, MA.
5. The Daughters of Edward Darley Boit, his most famous oil painting (featured below), hangs in the Museum of Fine Arts in Boston.
The Daughters of Edward Darley Boit, 1882, oil on canvas.
Answer: John Singer Sargent