Katharine (Kay) Muller Bullitt has served as a civic leader in Seattle since she moved to the area in 1953. Raised in Massachusetts, Bullitt earned a degree in government from Radcliffe College in 1946. She taught elementary school in Cambridge before settling in Seattle in 1953. Bullitt raised six children and dedicated herself to civic activism. She has been active in the areas of education, desegregation, civil rights, peace and international affairs, the arts, historic preservation, and environmental protection of the Pacific Northwest.

Bullitt's civic activism in the area of education is especially noteworthy. After teaching elementary school in Massachusetts, Bullitt was the founding trustee of the Little School, an independent day school located in Bellevue, Washington. She also served on the board of trustees, chairing the board from 1959-1967. Over the next twenty-plus years, Bullitt dedicated much of her time to specific education issues such as desegregation, public school funding, and school volunteer programs.

In 1968, Bullitt first became involved in desegregation through her work in organizing a voluntary racial transfer program between the Lowell and Madrona elementary schools located in Seattle. In the same year, the Seattle School District proposed the city's first magnet school. Garfield High School, located in the largely African-American populated Central Area, was chosen for conversion and marked the beginning of Seattle's desegregation work. School enrollment had dropped dramatically in the Central Area, and many of the area's schools were racially isolated. Community meetings were called in 1968 to discuss the Central Area's "school crisis." Bullitt attended the meetings as co-chair of Meany Junior High School's Parent-Teacher Association, a role in which which she served from 1968 to 1970. The meetings resulted in a proposal for a sub-district school board to represent the area's interests. An ad hoc agreement was signed with the Seattle School Board in January 1969, creating the Central Area School Council (CASC). The advisory council was composed of sixteen elected representatives, with ten members serving as advocates for the area's ten elementary schools. By 1970, CASC had become frustrated by the Seattle School Board's failure to include the council consistently in desegregation planning. In February 1971, CASC announced a school boycott to show the extent of local parents' support for the council, but the action was largely unsuccessful in enhancing CASC's influence in decision making.

In 1971, Kay Bullitt co-founded the Coalition for Quality Integrated Education (CQIE) with Betty Jane Narver. Bullitt served as president of the desegregation-focused non-profit organization until 1974. CQIE's purpose was to back the Seattle School Board's decision to develop desegregated middle schools by encouraging parental and community support and participation. CQIE was formed in combination with three groups: Coalition Concern, Citizens for Quality Integrated Education, and the School Affiliation Service. Coalition Concern formed in response to the Seattle School Board's 1970 proposed middle school desegregation plans and served primarily as an information resource group. Citizens for Quality Integrated Education was a citizen's committee formed by the Seattle School Board and composed of parents involved in the Seattle Public Schools' Voluntary Racial Transfer program. The program ran from 1963 to 1978, but a lack of white student volunteers inhibited its success. The School Affiliation Service (SAS) was formed by the American Friends Service Committee to create contacts and exchanges between schools in the United States and war-torn or developing countries. Caspar Sharples Junior High School contributed to Seattle's participation in SAS, working with schools in Japan. By 1974, CQIE had extended its focus from middle schools alone to all schools with racially mixed populations. From 1971 to 1977, CQIE published , a newspaper reporting on desegration for the parents of public school students. CQIE lost some of its grant funding in 1977 and was defunct by 1980.

Seattle has been described as the largest city in the United States to voluntarily desegregate its school system. In 1978, after the failure of voluntary busing, a mandatory busing program was enacted. The program was described in the , prepared by the Desegregation Planning Office of Seattle Public Schools. Nearly a quarter of the district's student population were bused out of their neighborhoods. Many parents were angered by the plan, and two months after mandatory busing began, voters passed an anti-busing initiative. The initiative was later ruled unconstitutional, and the Seattle School District continued mandatory busing until 1996.

Another major issue affecting education in Seattle revolved around public school funding and levy failures. In 1969, Bullitt participated in a protest walk to Olympia in hopes of persuading the Washington state legislature to allocate full funding to public schools. Her next contribution to school funding activism occurred in 1975, the year in which a double levy failure in Seattle resulted in school closures and staff layoffs. The Seattle School District created the Citizens' Levy Determination Process Committee to involve citizens in determining the following year's levy amount. The committee members decided instead to re-form as Seattle's Say on Schools (SSOS). Composed of members from the Parent-Teacher-Student Association, Seattle Chamber of Commerce, League of Women Voters, Central Area School Council, and Ad Hoc School Crisis Committee, SSOS had a far-reaching community presence. City-wide meetings were held to discuss school budget issues and to encourage widespread citizen involvement in the budget process. Bullitt served as a member of the SSOS steering committee during 1976.

The Ad Hoc School Crisis Committee was another group that formed as a result of the 1975 levy failure. Bullitt served as a member of the steering committee. The Ad Hoc School Crisis Committee proposed an alternative budget and plan that resulted in some immediate changes in the Seattle School Board's policies. Residual concern regarding school finances prompted the committee members to form a new, permanent organization. Citizens for Fair School Funding (CFSF) was founded in April 1976 by Diana Gale, Anne C. Hallett, and Betty Jane Narver. State-wide school finance reform became CFSF's focus. Bullitt served on CFSF's steering committee from 1977 to 1979. The steering committee established a statewide task force and developed a comprehensive legislative proposal to present to the Washington state legislature. The proposal limited the use of special levies in support of greater state funding, created a broader definition of a "basic education," and highlighted urban children as "special needs students." The 1977 Basic Education Act was passed largely due to CFSF's lobbying and proposal. CFSF ceased operation in 1979, but a new statewide organization took its place. The Citizens Education Center Northwest (CECN) was founded by Bullitt, Narver, and others. Bullitt served as a board member until 1987. CECN existed throughout the 1980s as an information resource, school advocate, and reform supporter.

Bullitt was also active in school volunteer programs to encourage greater citizen involvement in public schools. She co-founded the Volunteer Instruction Program (VIP) in 1967 and served as its chair from 1967 to 1970. VIP was designed as a supplemental program for Seattle public schools in the Central Area. It emphasized stimulating students of diverse class and racial backgrounds. VIP classes were taught by volunteers with various areas of expertise. Mary Bard Jensen, local children's author and sister of author Betty MacDonald, taught a playwriting class shortly before her death in 1970.

The Seattle School District encouraged greater citizen involvement through its Volunteer Services program. From 1970 to 1973, Bullitt served as the Central Area chair. The committee successfully ran volunteer recruitment campaigns, targeting retired citizens with the slogan, "Add a plus to life: involve yourself in a Seattle public schools volunteer career."

From 1983 to 1985, Bullitt served as a board member on the Washington State Temporary Committee on Educational Policies, Structure and Management. During that period, she was also chair of the Early Childhood Education Subcommittee. Bullitt was nominated by Evergreen State College President Daniel J. Evans to serve on the committee, which was formed as a result of state legislation (SB 3609). The bill created a temporary committee charged with "investigating the entire educational complex in Washington state" and making recommendations for improvement. The committee investigated all areas of education, including curriculum, higher education, and vocational education. Public hearings were held to secure testimony and statements from citizens and interested groups, as well as to elicit comments on drafts of the final report. The committee's findings were reported before the Washington state legislature in a 1985 report titled .

Bullitt was involved with other education-focused organizations as well. In 1979, she co-founded Private Initiatives in Public Education (PIPE) and served as a board member from 1979 to 1986. PIPE was a non-profit organization that allocated community resources to Seattle public schools. Partnerships were established between local businesses and high schools to better prepare students for careers. PIPE also managed an education grant fund to finance special school projects. During the period of Bullitt's involvement with PIPE, she was also a board member of the National Committee for Citizens in Education (1976 to 1986). The National Committee for Citizens in Education served as an informational resource for parents of public school students. Additionally, Bullitt served on the Board of Governors for the Evergreen State College Foundation from the early 1980s to 1990. The foundation is a financial advocate for Evergreen State College, a public, alternative college located in Olympia, Washington.

In addition to her activism on behalf of education, Bullitt supported civil rights causes. She was a board member of the Seattle Urban League in 1967-1973. Between 1974 and the the late 1990s, Bullitt served on the Washington State Advisory Committee to the U.S. Commission on Civil Rights and chaired the commitee between 1980 and 1983. She was also a board member of the Seattle Opportunities Industrialization Center between 1967 and 1989. From 1989-1991, she was a member of Seattle's Martin Luther King Memorial Committee.

Bullitt also actively supported historic preservation in Seattle. She was a board member of the Save Our Ships organization, later the Northwest Seaport, between 1963 and 1997, serving as president from 1979-1981 and 1985-1992. She also was a member of the Pioneer Square Historic Preservation Board between 1971 and 1982.

Bullitt's activism in international relations emphasized the achievement of peace. From 1991-1996, she was an organizing member of the Voices of Peace (Reconciliation) programs. Between 1984 and 1994, she was a board member of the Council of International Organizations, serving as the organization's president from 1986-1990. In 1982-1985, she was a member of multiple committees for Target Seattle: Preventing Nuclear War/Russian Realities. She also served as a delegation member for multiple sister cities: Mombasa (Kenya) and Limbe (Cameroon) in 1988, Managua (Nicaragua) in 1984, and Tashkent (USSR) in 1983.

Bullitt also supported the arts in Seattle. She was a member and chair of the executive committee for Bumbershoot, a Seattle arts festival. She also was a board member for the Northwest Chamber Orchestra between 1981 and 1985.

In 1976, Bullitt helped found a women's bank, the Sound Savings and Loan, and served as director until 1986. Additionally, beginning in 1983 she served as trustee for the Bullitt Foundation, which promotes environmental protection in the Pacific Northwest.

Among the awards bestowed on or established in honor of Katharine Bullitt for her civic contributions are the Jefferson Award for Public Service, the YMCA Milnor Roberts Award for World Peace through International Understanding, the Partners in Public Education (PIPE) Katharine Muller Bullitt Award (named for her as the organization's co-founder), the Ralph Bunche Award from the Peace through Law Section of the Seattle Bar Association, the Paul Beason Award from Washington Physicians for Social Responsibility, and the United Nations (Seattle Chapter) Human Rights Award.

Bullitt planned to deed her family home in Capitol Hill to the city of Seattle for use as a public park after her death.