Marguerite de Angeli was born in Lapeer, Michigan on March 14, 1889. The daughter of a photographer and one of six children, de Angeli developed a love for literature early on in her life. De Angeli married the violinist John Daly de Angeli, with whom she had three children. Starting in 1921, de Angeli began doing illustrations for a Baptist and Presbyterian Sunday school paper, which lead her eventually to the world of children's literature.
De Angeli's first story was a picture book about young children, which went on to become the preliminary book in the Ted and Nina Series. One of her favorite subjects to write about was communities of Lancaster County, Pennsylvania, featuring them in books like Yonie Wondernose (1944), which depicts the Amish. Her most famous novel is The Door in the Wall, a 1949 children's story about a young knight-in-training named Robin. For this book, de Angeli was awarded the prestigious Newberry Medal in 1950. De Angeli also penned an autobiography, Butter at the Old Price, in 1969. By the time of her passing in 1987, de Angeli had written and illustrated 28 books.