Ethel attained Bachelor of Arts degree, graduating from Douglass College in 1938. Some time later, she contunied her studies at Harvard Graduate School of Education, graduating in 1964. Heins also received honorary doctorate at Simmons College in 1985.
Ethel Heins began a long-time career as a children’s librarian in 1938 at the New York Public Library, a post she held till 1943. In 1955 Ethel accepted a position at the Boston Public Library, where she stayed until 1962, when she left for the Lexington Public Schools System in Massachusetts as an instructional materials specialist. In 1962 Heins also began writing reviews for Horn Book magazine, a children’s journal that her husband edited. By 1974 Heins took over the editorship, a post she held for the next ten years.
Mrs. Heins was a founder of the Center for the Study of Children's Literature at Simmons College in Boston, where she also taught as an adjunct professor for 10 years.
In 1989 Ethel Heins acted as a jury member of Biennial of Illustration Bratislava.
Ethel also lectured at several colleges in the Boston area and throughout the United States and Europe.
Ethel was a member of American Library Association, New England Library Association, New England Roundtable of Teen and Children's Librarians, Children's Literature New England, Inc. and International Board on Books for Young People.
Ethel married Paul Heins on June 27, 1943. The couple gave birth to two children — Peter S. and Margery E. Heins.