Hilda van Stockum was born in Rotterdam, The Netherlands, and grew up there, near Amsterdam, and in Ireland, the only child of Capt. Bram van Stockum, an officer in the Dutch Royal Navy, and his wife Olga Boissevain.
Her maternal grandfather Charles Boissevain was an editor of the Algemeen Handelsblad, an influential Dutch newspaper. Hilda began writing as a child. She attended art school in Amsterdam and later in Dublin, where she met her future husband, Ervin Ross "Spike" Marlin, a friend of her brother Willem van Stockum, later an important mathematician. The couple married in 1932 and had six children who featured in many of her books.
By 1935, the family was living in Washington, D.C., where Marlin worked for the Social Security Administration. Later Hilda and the children accompanied him to other assignments in Ireland and London.
She translated books from the Dutch, worked as a freelance children's book illustrator, and wrote a dozen of her own children's books, beginning with A Day on Skates (1934), which won a Newbery Honor. Over the next four decades, she produced a book a year. She memorialized her brother Willem, who was killed piloting a bomber over France in World War II, in her book The Mitchells (1945). Perhaps her best known work was The Winged Watchman (1962), based on a true story about the Dutch Resistance in World War II. In the 1960s and 1970s, Hilda began concentrating on more ambitious painting projects and shows of her work were held at galleries in Dublin, Geneva, Ottawa, and Washington. In 1993, her still life "Pears in a Copper Pot" appeared on an Irish postage stamp as part of a series honoring contemporary art.