Sister Katherine "Kate" McDonnell, 89, who helped found Washington's Sursum Corda housing complex and Housing Counseling Services, died of a heart attack June 29 at the Kenwood Convent of the Sacred Heart in Albany, N.Y., where she had lived since 1998.

Sister McDonnell, a 60-year member of the Religious of the Sacred Heart Catholic order, was among the nuns who helped establish Sursum Corda Cooperative, a housing development on North Capitol Street. She was one of the six nuns who lived in the complex when it opened in 1969 and was there through 1983, the year the archdiocese gave the group a service award.

Sursum Corda, Latin for "Lift Up Your Hearts," is now a haunt of drug dealers and gangs, but when the complex opened, it was envisioned as an oasis for the District's poor. The last resident nun, Sister Helen McCulloch, left the complex about four years ago because of increasing violence.

Sister McDonnell, who had spent decades as a teacher and school administrator, became a housing advocate for the poor after her experiences with Cuban immigrants in Miami and after the Second Vatican Council, which encouraged many religious members to engage in nontraditional work.

In 1972, she submitted a proposal to the Department of Housing and Urban Development for a program to train housing professionals in counseling. Within a few days, she received a grant that enabled her to open Housing Counseling Services at 2436 18th St. NW. It became one of the city's most influential housing agencies, negotiating with landlords and creditors, helping poor renters convert rental buildings to cooperatives and condominiums, and assisting new homeowners.

Sister McDonnell retired as the agency's director in 1987. She worked until 1993 assisting the director of New Endeavors by Women, a program offering support to homeless women attempting to recover from addiction and improve their lives. From 1993 to 1998, she worked with New Expectations, an educational program in the District.

Sister McDonnell was born in New York and, after studying interior design for two years, entered the International Society of the Sacred Heart as a novice in 1936. She professed her first vows in the society in 1938 and her final vows in 1944.

In 1948, she graduated from Manhattanville College in Purchase, N.Y. Four years later, she received a master's degree in educational administration from Villanova University.

Sister McDonnell was a teacher and administrator in the society's schools in Rochester, N.Y., Philadelphia and Newton, Mass. In the 1950s, she was headmistress of the society's two academies in Philadelphia. Later, she became the first headmistress of an academy in Miami established to help with the educational needs of children of the first wave of Cuban refugees. In Miami, she also became familiar with the plight of migrant farmworkers and later said it was visiting the migrant camps that made her realize "the poor have no options."

Sister McDonnell was a recipient of the Claire Dunn Award, given by Network: a Catholic Social Justice Lobby for her work on behalf of the poor. Sister McDonnell was among Catholic sisters who helped establish the lobby in the early 1970s.

Sister McDonnell served on the boards of many social service agencies in Washington, including two she helped establish: the Citywide Housing Coalition and La Morada Shelter for men. She was also a member of the D.C. Commission on the Homeless.

Survivors include a sister.