[1] He learned painting in 1877, under the tutelage of painter William Howard Hart (1863-1937).

[1] From 1882 to 1886, he studied painting at the National Academy of Design under the tutelage of Walter Satterlee (1844-1908), and at the Art Students League of New York under James Carroll Beckwith (1852-1917).

[1] From 1888 to 1889, he studied at the Académie Julian in Paris under Jules Joseph Lefebvre (1836-1911) and Jean-Joseph Benjamin-Constant (1845-1902).

[1] Whittemore became an Associate at the National Academy of Design in 1897 and became a founding member of the American Society of Miniature Painters in 1899.

[1] After his first wife died, he married another painter, Alice Charlotte Simpson (1863-1955).