Lally Weymouth, a globe-trotting journalist and socialite who belonged to the Graham family that owned The Washington Post for 80 years, and who carved her own niche securing hard-to-land interviews with foreign leaders, including Saddam Hussein, Yasir Arafat and Muammar el-Qaddafi, died on Monday at her home in Manhattan. She was 82.

The cause was pancreatic cancer, her daughter Katharine Weymouth told The Post.

Ms. Weymouth was the granddaughter, daughter, sister and mother of publishers of The Post. But she was never given a leadership role at the paper, which by some accounts she desired, in part because women of her generation were not put on a track for such jobs.

Ms. Weymouth’s maternal grandfather, the banker and financier Eugene Meyer, bought The Post out of bankruptcy in 1933. He named his son-in-law, Philip L. Graham, publisher in 1946. After Mr. Graham’s death by suicide in 1963, leadership passed to his widow, Katharine Graham, who overcame her inner fears and lack of preparation to preside steadfastly over the paper’s Pulitzer Prize-winning coverage of the Watergate scandal, which led to the resignation of President Richard M. Nixon in 1974.

Although Ms. Weymouth was the oldest of four children — and the only daughter — Mrs. Graham anointed her oldest son, Donald, as her successor in the early 1970s. Said to be wary of family competition, Mrs. Graham wanted just one of her children involved in running the paper, Roswell L. Gilpatric, a Graham family lawyer, told the author Carol Felsenthal for an unauthorized 1993 biography of Mrs. Graham, “Power, Privilege and The Post.”

Ms. Weymouth resented being left out, Edward Kosner, a former editor of New York magazine, where she was a contributor, said in an interview. On the other hand, she was motivated to carve out a career on her own. “I think her family situation drove her ambition,” Mr. Kosner added.

In a 2011 interview with Washingtonian magazine, Ms. Weymouth said she never aspired to run The Post. “Mom decided on one child — Don,” she said. “I didn’t want to go to The Post. I wanted to make it on my own.”