Ellen Wetherald Ahrens was born in Baltimore, Maryland, in 1859. She studied art at the School of the Museum of Fine Arts in Boston, at the Pennsylvania Academy of the Fine Arts, where she studied under Thomas Eakins, and at the Drexel Institute, where she studied under Howard Pyle in 1897. During this time she shared a studio at 1523 Chestnut Street in Philadelphia with Jessie Willcox Smith and Violet Oakley, two other Pyle students.

Later she attended the Carnegie Institute to further her studies in portraiture. Ahrens was a member of the Pennsylvania Society of Miniature Painters, the Philadelphia Plastic Club, and the Philadelphia Water Color Club. She exhibited her works at the the Pennsylvania Academy of the Fine Arts, where she won the second Toppan Prize in 1884, at the Carnegie Institute, where she won the silver medal in 1901, and at the St. Louis Exposition in 1904.

In the November 1901 issue of International Studio, Charles H. Coffin describes her work Sewing:   A Portrait, for which Ahrens won the silver medal at the Carnegie Institute:

It is certainly a very faithful study of character...and it is very truely drawn and satifactory in values...but almost painfully methodical, austere in color and quite undistinguished for style.

Examples of her illustrations can be found in the books Jo's Boys by Louisa May Alcott and A Maid of Bar Harbor by Henrietta Gould Rowe.