Johnston won a write-in campaign for school board in 1977, and won a second four-year term in 1982. She served two terms as board president.
A native of Boston, Mass., Johnston earned a degree in chemistry from Simmons College. She moved to Palo Alto in 1961 so her husband, Jim, could take a position as an assistant professor in Stanford University's Mechanical Engineering Department. They had two young daughters at the time.
In 1963 they built a home on the Stanford campus and later had three more children. Four of the five graduated from Gunn High School, and the fifth opted to finish high school at Palo Alto High School.
In the 1980s, Johnston was a founding member of the fundraising group Palo Alto Foundation for Education (PAFE), which later became part of the current Palo Alto Partners in Education (PiE). PiE last year raised $3.4 million for Palo Alto public schools.
Over the years, Johnston was active in a variety of community groups, including Parents Nursery School and the League of Women Voters.
"The League and the coop nursery played a crucial role in my life and friends made in the League and Parents Nursery School are still friends today," she later wrote in an autobiographical description.
She was also active with the Palo Alto Woman's Club, where she was a member of the "knit-stitch group" and served as finance chair from 2009 to 2011.
Johnston held a variety of jobs, including development director and director of alumni relations at Stanford Law School. In retirement, she was on the advisory board of the Foundation for a College Education and on the board of the California Consortium of Education Foundations.
Johnston is survived by her husband, Jim; five children, Susan Coote of Wayne, Penn.; Patricia Moore of Athens, Ga.; John Johnston of Redwood City; Anne Schultz of Los Altos and Thomas Johnston of Sunnyvale; 13 grandchildren; a sister, Gail Carter of Rochester, N.H.; and a brother, William of Eliot, Maine.
Memorial contributions may be made to the Foundation for a College Education (www.collegefoundation.org) of East Palo Alto.