Gillian Flynn, was born in Kansas City, Missouri on February 24, 1971. She grew up in a neighborhood in the heart of Kansas City with her Mother, Judith Ann, her father, Edwin Flynn, and her older brother Travis. Both her parents were college professors at the University of Missouri in Kansas City. Her mother, Judith, was a reading comprehension teacher, and her father, Edwin, was a film professor.  Flynn was often described as a shy child, one who found solace reading in the corner and watching movies with her father. At a young age Flynn enjoyed reading books that involved adventure and true crime, she read books like A Wrinkle in Time and In Cold Blood  around the age of 10 years old.  After high school, Flynn attended the University of Missouri in Kansas City achieving a bachelor's degree in journalism and English. She then attended Northwestern University and graduated with a masters degree in Journalism.  With the intent of becoming a crime reporter, Flynn worked as a stringer journalist for the News & World report center. Years later she acquired a job at the Entertainment Weekly magazine working as a writer creating articles, blogs, and more for the magazine. She also worked as a television critic, but then was terminated in 2008 due to budget cuts. However, that didn't stop her from full-filling that dream of being a crime reporter. She began dedicating her time to being a full time fiction novel author, crafting stories that are often complex, physiological thrillers, and exploring the unthinkable.

Most of Gillian Flynn's inspiration for writing comes from her childhood. As a shy child, she spent much of her time reading, telling stories, and watching films. This early exposure created a passion for storytelling and helped her develop a diverse and sophisticated vocabulary. Additionally, having both parents as college professors had a significant influence on her. Through watching her father teach and analyze film, she absorbed her father's passion as her own. She also gained strong grammar and language skills from her mother, who was an English professor.

Flynn’s writing style is deeply shaped by these influences. She is known for her dark, psychological, and twist-filled stories. Her characters often possess deep psychological complexity, struggling with internal demons and moral ambiguity ("grey area"). Flynn also creates unreliable narrators, which forces readers to question the truth and adds suspense and mystery to the plot. Her use of plot twists further enhance that suspense and mystery in her plot.  Additionally, her work challenges traditional stereotypes and explores the complexities of human nature through dark themes.