[6] The Foundation has grantmaking programs in education, the environment, global development and population, the performing arts, and philanthropy.

[7] Founding board members were Bill, Flora, and the couple's oldest son, Walter Hewlett.

In its first ten years, the foundation awarded close to $15.3 million to organizations involved in education, population, performing arts, environment, health, and social services.

[10] Shortly after, the foundation appointed former University of California Chancellor Roger W. Heyns as president, with Bill Hewlett becoming the board chair.

[12] In 1993, with the appointment of former University of California President David P. Gardner,[13] who succeeded Roger Heyns who retired after 15 years, the foundation's focus widened.

The foundation expanded its funding of environmental causes, formerly restricted to California, to all over the Western United States and Canada.

[16] During Brest's time as president, the foundation started to focus on awarding grants for efforts curbing global warming and the expansion of the use of open educational resources.

[27] In 2007, the Hewlett Foundation made a $113 million donation to the University of California, Berkeley to create 100 new endowed professorships and provide financial help for graduate students.

[31] Hewlett funded restoration of the Bay Area Salt Ponds[32] and conservation of the Great Bear Rainforest in Canada.

[33] Hewlett's Environment Program makes grants to support conservation in the North American West, reduce global warming and conventional pollution resulting from the use of fossil fuels, and promote environmental protection efforts in California.

[35] The Hewlett Foundation make grants in developing countries and in the United States to provide and advocate for family planning and reproductive health services.

[37][38] The following table lists the top sectors to which the Hewlett Foundation has committed funding within its Global Development and Population Program.