Her instructor and later employer, William Morris Hunt, was the subject of a portrait she made and several books; she is considered his principal biographer.

[4] She studied under the supervision of artist and teacher William Morris Hunt, who had an "experimental approach" towards art, starting in 1868.

[4] Despite criticism from those who thought he was wasting his time, Hunt offered his female students technical skills, inspiration, and a sense of self-worth.

Hunt empowered these early women artists, but Knowlton maintained their circle of support and friendship.In the 1880s she studied under Frank Duveneck in Munich, Germany.

[6] In the summer of 1881 Knowlton was Duveneck's student in Gloucester, Massachusetts, where he held art classes "between trips to Europe."

Her first portrait, made of William Morris Hunt, was exhibited at the Museum of Fine Arts in Boston.

[11] Upon Hunt's death, Knowlton was a contributor a fund for a dedicated room of his works in the Museum of Fine Arts, Boston.

[12] She also helped to coordinate a retrospective of his work in Boston at the Museum of Fine Arts and was his "principal biographer.