After teaching tenth-grade world history for two years and living in northeast Brazil for two years with the Peace Corps, Brown directed the single-subject credential program at Dominican University of California at San Rafael from 1982 to 1992.
Using the term Big History, coined by David Christian at Macquarie University in Sydney, Australia, Brown told the whole story from the Big Bang to the present in simple, non-academic language to convey our common humanity and our connection to every other part of the natural world.
She served as a founding board member of the International Big History Association (IBHA).
Brown died of pancreatic cancer on October 15, 2017, at her home Berkeley, California, surrounded by family.
Brown was an American Book Award recipient in 1987 for Ready From Within: Septima Clark and the Civil Rights Movement.