Born in 1935, in Burnham, Buckinghamshire, Susan Cooper lived in Buckinghamshire until she was 21, when her parents moved to her grandmother's village of Aberdovey, Wales. She attended Slough High School and then earned a degree in English from the University of Oxford.

After graduation, she worked as a reporter for The Sunday Times of London under Ian Fleming, and wrote books in her spare time. During this period, she began work on the Dark Is Rising sequence and finished her first book, the science fiction novel Mandrake.

In 1963 she left Britain for the United States to marry a professor at the Massachusetts Institute of Technology. She then began writing full-time, focusing on The Dark Is Rising series and the 1970 Dawn of Fear, based on her childhood wartime experiences. Her output would eventually encompass works of fiction for both children and adults, a series of picture books, film screenplays, and works for the stage.

In July 1996, Cooper married Canadian-American actor and her sometime co-author Hume Cronyn, the widower of the late Jessica Tandy. They remained married until Cronyn's death in June 2003. Cooper currently lives in Marshfield, Massachusetts.

The Dark Is Rising sequence

• Over Sea, Under Stone (1965)
• The Dark is Rising (1973)
• Greenwitch (1974)
• The Grey King (1975)
• Silver on the Tree (1977)

Other novels

• Mandrake (1964)
• Dawn of Fear (1970)
• Seaward (1983)
• The Boggart (1993)
• The Boggart and the Monster (1997)
• King of Shadows (1998)
• Green Boy (2002)
• Victory the story of Samuel Robbins a boy who served on HMS Victory at the Battle of Trafalgar (June 2006)

Picture books for children

• Jethro and the Jumbie (1979)
• The Silver Cow (1983)
• The Selkie Girl (1986)
• Matthew's Dragon (1991)
• Tam Lin (1991)
• Danny and the Kings (1993)
• Frog (2002)
• The Magician's Boy (February 2005)

Movies

• The Seeker (2007)