[3] Fritz was born to American Presbyterian missionaries Arthur Minton Guttery and the former Myrtle Chaney in Hankow, China, where she lived until she was twelve.
[4][3] Growing up, she attended a British school and kept a journal about her days in China with her amah, Lin Nai-Nai.
[6] Fritz's writing career started with the publication of several short stories in Humpty Dumpty magazine early in the 1950s.
Her first book, Bunny Hopwell's First Spring, was published in 1954 and followed in 1955 by 121 Pudding Street, a work based on her own children.
Her autobiography, Homesick, My Own Story (1982), won a National Book Award for Young People's Literature in the Children's Fiction category[8] and was a runner-up for the Newbery Medal.