Harper was raised in northwest Oregon. Her father had worked in a nuclear lab analyzing radioactive cloud samples from Russian atomic test blasts; her mother had been a uranium buyer. Her first electronic toy was an oscilloscope. Between a father who was a meteorologist, woodworker, luthier, and otherwise jack-of-all-trades, and a mother who was an accomplished horsewoman, seamstress, musician, and community activist, Harper had a difficult time choosing between life goals. She did know by the time she was eleven that she would become an astronaut, a stunt person, or a science writer. However, her interests continue to range from fencing to forensics. She is a violinist and composer who also studies voice, paints in oils, sculpts in stone, and collects dryer lint. She plays the dulcimer that her father built; and plays blues and folk guitar, even though she can never find her favorite pick.
In 1979, Harper won a journalism honor and a communications scholarship, and enrolled at the University of Oregon. She worked nights in a cannery, fished to feed her cat, and lived in a filbert orchard while studying physics, mathematics, and journalism. Uncertain as to whether she should pursue a career in physics, music, writing or space science, she attended the Oregon Institute of Marine Biology. At the same time, she served an internship as science journalist on The World newspaper (Coos Bay, Oregon).
In 1984, Harper graduated from the University of Oregon with a Bachelor of Science. She returned to northwest Oregon and immediately took a job with a company in R&D high-tech, test and measurement. This allowed her to make enough money to support her personal research in engineering, genetics, virology, and other disciplines. Her fiction writing was, at that time, a hobby.
By the end of 1988, Harper had completed four science-fiction novels. Under forcible pressure from a friend, she sought an agent. Her first novel was accepted at Del Rey Books (an imprint of Random House) six months later, and she saw Wolfwalker published in 1990. The novel was an immediate best-seller, and Harper's career moved quickly forward.
Currently, Harper is the author of nine science-fiction novels, including the best-selling and critically acclaimed Wolfwalker series and Cat Scratch series, as well as other stories. Her work is available internationally in a variety of languages and as books on tape. Two of her novels, Cat Scratch Fever and Wolf's Bane, were nominated for the Oregon Book Awards. She has also received numerous awards for science writing, has been Guest of Honor at several conventions, and was nominated in 1999 to a University of Oregon inaugural Hall of Achievement. In late 1999, she was a guest speaker at the Library of Congress, in Washington, D.C..
Professionally, Harper has worked for over 20 years as a science editor and writer in fields as diverse as software engineering, high-speed microwave (satellite, not kitchen appliances) wafer communications, superconductor and microprocessor technology, medical sciences, genetics, and herpetology. It is this continuing background in R&D medical science, high-tech, forensics, and other disciplines that Harper credits with being the inspiration for the science in her fiction novels.
Harper credits the realism of the action in her novels to a lifetime of competition and participation in outdoor and athletic activities. She attributes her overall success as a novelist to a diverse academic background; extensive experience in fending off wild and feral animals; a continuing involvement in science; and in-depth experiments in drowning. Other activities have included archery, shooting, rock-climbing, waterpolo, soccer, sailing, scuba diving, fencing, and martial arts. In the latter two fields, she competed nationally and internationally. Active in community service, Harper currently teaches creative writing for an alternative school, trains youth in wilderness skills, and serves on the board of directors for a youth treatment center.