J. Francis Harris III, 62, a real estate broker and developer here for 33 years, died of a heart attack Friday at Georgetown University Hospital where he was being treated for a heart condition.

Mr. Harris moved to Washington in 1945 and went into the real estate business. He was a partner in the Rodenberg Realty Corp. for several years before opening his own real estate and development business in Georgetown in the early 1950s. After a few years in semi-retirement, he joined the Vicki Bagley real estate firm about a year ago.

Among his real estate developments in the Georgetown area is Suter's Lane, a row of houses named for John Suter of Suter's Tavern fame, an ancestor of Mr. Harris' first wife, the former Sylvia Sutter.

Mr. Harris was born in Boston, Mass, and graduated from Boston University.

During World War II, he served as a Marine Corps fighter pilot, having transferred there from the Royal Canadian Air Force when the United States entered the war.

In addition to his home in Georgetown, he maintained a summer home in Cape May, N.J., for many years and, later, in palm Beach, Fla.

He was a member of the Kiwanis Club of Washington, and the Black Tie Club of Georgetown.

Survivors include two daughters, Carol Harris of Washington and Donna Gamal of Harper's Ferry, W.Va.