Johnson grew up in Youngsville, Pennsylvania. After high school, she enrolled at Indiana University of Pennsylvania but dropped out after a few weeks and enlisted in the Navy in 1971, serving at Clark Air Base in the Philippines.
She wrote about her experience of the Service in her 1986 book Making Waves: A Woman in This Man's Navy. She later transferred to the U.S. Marine Corps. On leaving the Marines, she gained a master's degree in teaching English and, in 1989, went to teach at Carlmont High School in Belmont, California.
