Oglesby died Tuesday at his home in Montclair, N.J. Todd Gitlin, a friend and fellow activist who went on to write about the era, said Oglesby had been fighting lung cancer that spread throughout his body.
"The only other person who compared to him was Martin Luther King," Gitlin said. "He had the mastery of vivid phrases and also the power of mobilizing people."
The SDS had been founded in 1960 at the University of Michigan, and its early declaration, the Port Huron Statement, helped embody the idealism of the early '60s. The SDS supported civil rights and opposed the nuclear arms race. It was strongly critical of the U.S. government, and called for greater efforts to fight poverty and big business. By the mid-'60s, when Oglesby joined, the United States had committed ground troops to Vietnam and the SDS had expanded nationwide, with a more radical purpose, one well captured by its new president.
Oglesby helped organize teach-ins and rallies, and his power peaked in November 1965 with his speech at an early, and massive, antiwar rally in Washington. In an address titled "Let Us Shape the Future," Oglesby spoke as a disillusioned patriot and liberal who rejected not just the war, but much of American foreign policy since the end of World War II and the free enterprise system he believed demanded endless conflict. He was equally critical of Republican and Democratic presidents as victims, and enablers, of the corporate state and insisted the country's founders would have been on his side.
"Our dead revolutionaries would soon wonder why their country was fighting against what appeared to be a revolution," he declared.
In his most memorable phrase, he challenged those who called him anti-American: "I say, don't blame me for that! Blame those who mouthed my liberal values and broke my American heart."
In recent years, Oglesby became obsessed with the assassination of President Kennedy. He wrote the books "Who Killed JFK?" and "The JFK Assassination" and contributed an afterword to Jim Garrison's "On the Trail of the Assassins." In 2008, his memoir "Ravens in the Storm" was published. He also recorded music and taught at Dartmouth College and the Massachusetts Institute of Technology.
Survivors include his partner, Barbara Webster, and three children.