Larry Kramer, the noted writer whose raucous, antagonistic campaign for an all-out response to the AIDS crisis helped shift national health policy in the 1980s and ’90s, died on Wednesday morning in Manhattan. He was 84.

His husband, David Webster, said the cause was pneumonia. Mr. Kramer had weathered illness for much of his adult life. Among other things he had been infected with H.I.V., the virus that causes AIDS, contracted liver disease and underwent a successful liver transplant.

An author, essayist and playwright — notably hailed for his 1985 autobiographical play, “The Normal Heart” — Mr. Kramer had feet in both the world of letters and the public sphere. In 1981 he was a founder of the Gay Men’s Health Crisis, the first service organization for H.I.V.-positive people, though his fellow directors effectively kicked him out a year later for his aggressive approach. (He returned the compliment by calling them “a sad organization of sissies.”)

He was then a founder of a more militant group, Act Up (AIDS Coalition to Unleash Power), whose street actions demanding a speedup in AIDS drugs research and an end to discrimination against gay men and lesbians severely disrupted the operations of government offices, Wall Street and the Roman Catholic hierarchy.

“One of America’s most valuable troublemakers,” Susan Sontag called him.

Even some of the officials Mr. Kramer accused of “murder” and “genocide” recognized that his outbursts were part of a strategy to shock the country into dealing with AIDS as a public-health emergency.