George W. Hart Jr., 49, a community activist in the Cardoza section of Northwest Washington who had been an associate of Mayor Marion Barry Jr. and the Rev. Douglas Moore, a former member of the D.C. City Council, died at his home in Washington Sunday after a heart attack.

Mr. Hart, a native Washingtonian, attended elementary and junior high schools here and later took courses at Georgetown University. But much of his education occurred in the streets of the city and in various prisons.

In the 1960s, he emerged as a spokesman for blacks in the inner city. He was associated with Barry when the future mayor was head of Pride Inc., a federally funded self-help organization in the inner city, and with Moore when the future City Council member was planning director of the Reconstruction and Development Corp., which was funded in part by the Ford Foundation.

Mr. Hart also was active for many years with CHANGE Inc., which was financed by the RDC, and with the Concerned Citizens of Central Cardozo. fHe was a longtime member of St. Stephen and the Incarnation Church, where he was a member of the vestry, and of the Black United Front.

Mr. Hart's survivors include three daughters, Michele, Beverly and Annise; a brother, Bilah Shahid, and two sisters, Malissa E. Jones and Sarah L. Warrick, all of Washington.