Harriet Ziefert grew up in New Jersey, where she attended the local schools. She graduated from Smith College, then received a Master's degree in Education from New York University, where she was among the founding pioneers in the development and teaching of what today is known as the Common Core Curriculum. Since then, she has written more than 200 books.

Ziefert's picture book A New Coat for Anna, illustrated by Anita Lobel, was chosen as one of 10 books to be read aloud by former First Lady Barbara Bush as part of a program promoting reading. In addition to her prolific picture-book writing, Ziefert has authored many innovative easy-to-read books, including Sleepy Dog, which has sold more than two million copies. Ziefert's relationship with illustrator Simms Taback yielded over a dozen books that have become modern classics.

As the publisher of Blue Apple Books, Ziefert launched the award-winning Jump-Into-Chapters series, which includes Scribbles and Ink, now a WGBH televised series. As a packager, Ziefert delivered the Caldecott honor-winning There Was an Old Lady Who Swallowed a Fly. The mother of two and grandmother of five, Ziefert lives in the Berkshires of Massachusetts.