Jean Fritz was born on November, 16, 1915, to parents Arthur and Myrtle Guttery. At the time Fritz was born, her parents were missionaries in Hankow, China. In Jaqueline Weiss' Profiles in Children's Literature, Fritz discusses her childhood in a 1974 interview. She talks about her lovely childhood in which her family took "pleasant vacations at Peitaiho, a Pacific Ocean resort north of the capital, Peking [... and we] enjoyed picnics where the Great Wall meets the sea." Fritz's family lived in China for 13 years and during this time, she went to British schools for her education. However, on April 26, 1928, Fritz and her family fled the country on the President Taft because of many riots against Westerners and Chinese landlords.

The ship took the Guttery family to San Francisco from where they drove to Washington, Pennsylvania. The family lived in Pennsylvania for a year before Fritz's father received a job offer in Hartford, Connecticut. Throughout this time, Fritz attended local public schools to receive her education. She eventually went on Wheaton College in Norton, Massachusetts—she graduated in 1937 with an English degree. While in college, Fritz wrote for the campus newspaper, the Wheaton News. According to Contemporary Authors Online, Fritz had always wanted to be a writer—she wrote poems and short stories in high school, and she always kept a journal to which she often referred to when she was older and writing children's stories.

After college, Fritz moved to Manhattan, New York, with her parents. She worked as a textbook researcher at the Silver Burdett Company. This job as a textbook researcher was supposed to be temporary, but it lasted until 1941. During this time, she also took courses, including a children's literature course taught by Jean Betsner, at Columbia University. Betsner encouraged Fritz to submit her term paper, "Style in Children's Literature," to Elementary English to see if she could get published there; it was included in the October 1941 issue and was her first published work.

One month after her first paper was published, the then Jean Guttery married Michael Fritz, an active army officer in the Second World War. Throughout the first years of their marriage, the Fritz's moved around often. After living in New York, they moved to San Francisco, and then Fort Lewis in Tacoma, Washington. In each state, Fritz worked for local newspapers reviewing books, both adult and children's books. After the end of the war, the couple (along with their first child, David) moved in with her parents in New York City. It was there that Fritz had her second child, Andrea.

Soon thereafter, the Fritz family moved to Dobbs Ferry, New York, in 1951, where Fritz was a volunteer in the public library. It was in this library where she established a children's department, for it did not have one. According to Weiss, the children's department became so popular that Fritz was hired as a full-time employee. After working in the children's department at the library for a while, Fritz left in order to pursue her writing career. In 1954, Fritz published her first children's book, Fish Head, at Coward-McCann. Fritz is quoted by Weiss stating the premise of the book, "It's a funny story about a cat stowaway on a fishing boat who has to find his sea legs." Four years later, Fritz published her first historical fiction book, The Cabin Faced West, again with Coward-McCann. According to Contemporary Authors Online, The Cabin Faced West is based on "a favorite family story about her great-great-grandmother and the day Gen. George Washington had supper in her home." In between writing children's books Fritz also taught a writing workshop in the public library of Katonah, New York, where she lived. According to Contemporary Authors Online, Fritz's workshop, the Jean Fritz Writers' Workshop, was established in 1962.

Throughout the rest of her career, Fritz wrote many children's novels, book reviews, and adult short stories. The Cabin Faced West was the beginning of her fascination with historical fiction books for children. She also wrote biographies for young adults about Pocahontas, Christopher Columbus, Sam Houston, Benedict Arnold, Harriet Beecher Stowe, Stonewall Jackson, James Madison, Theodore Roosevelt, and Benjamin Franklin. Stephanie Loer considers The Double Life of Pocahontas, a book that emphasizes the Indian princess' admiration of John Smith and her place in America and Europe, to be a great work of detailed research and states that Jean Fritz "has created a very human character trapped between two cultures." The book also contains information regarding the relationship between the colony of Jamestown and Powhatan, Pocahontas' father.

Fritz received many awards throughout her life for her exemplary writing of children's and juvenile books: all of her books have been recognized at least once. A few of the books that have received awards are Homesick: My Own Story has received two honors, the Newbery Honor Book and the American Book Award; Stonewall was a Boston Globe-Horn Book; a New York Times Outstanding Book; and San Francisco which was a Junior Literary Guild Outstanding Book.

Altogether, Fritz received five Boston Globe-Horn Book Honor Book awards, 1973, 1976, 1979, 1981, and 1983; many Notable Children's Book awards; the Newbery Honor Book award, 1983; the Notable Children's Trade Book in the Field of Social Studies award, 1985; the Regina Medal, 1985; the Laura Ingalls Wilder Award, 1986; the University of Southern Mississippi Medallion, 1988; the 1978 Outstanding Author or Illustrator Award from the Pennsylvania School Librarian's Association; the American Book Award; the New York Times Outstanding Book Award; and the Junior Literary Guild Outstanding Book Award.

Jean Fritz is currently living in Dobbs Ferry, New York. Her two children, both married with their own families, live near the writer. Fritz, her children, and her grandchildren all enjoy spending time together.