Zinn died of a heart attack in Santa Monica, Calif., daughter Myla Kabat-Zinn said. The historian was a resident of Auburndale, Mass.
Published in 1980 with little promotion and a first printing of 5,000, "A People's History" was - fittingly - a people's best-seller, attracting a wide audience through word of mouth and reaching 1 million sales in 2003. Although Zinn was writing for a general readership, his book was taught in high schools and colleges throughout the country, and numerous companion editions were published, including "Voices of a People's History," a volume for young people and a graphic novel
"I can't think of anyone who had such a powerful and benign influence," said the linguist and fellow activist Noam Chomsky, a close friend of Zinn's. "His historical work changed the way millions of people saw the past."
At a time when few politicians dared even call themselves liberal, "A People's History" told an openly left-wing story. Zinn charged Christopher Columbus and other explorers with genocide, picked apart presidents from Andrew Jackson to Franklin D. Roosevelt and celebrated workers, feminists and war resisters.
Even liberal historians were uneasy with Zinn. Arthur M. Schlesinger Jr. once said: "I know he regards me as a dangerous reactionary. And I don't take him very seriously. He's a polemicist, not a historian."
In a 1998 interview with The Associated Press, Zinn acknowledged he was not trying to write an objective history, or a complete one. He called his book a response to traditional works, the first chapter - not the last - of a new kind of history.
"There's no such thing as a whole story; every story is incomplete," Zinn said. "My idea was the orthodox viewpoint has already been done a thousand times."
"A People's History" had some famous admirers, including Matt Damon and Affleck. The two grew up near Zinn, were family friends and gave the book a plug in their Academy Award-winning screenplay for "Good Will Hunting." When Affleck nearly married Jennifer Lopez, Zinn was on the guest list.
"He taught me how valuable - how necessary dissent was to democracy and to America itself," Affleck said in a statement. "He taught that history was made by the everyman, not the elites. I was lucky enough to know him personally and I will carry with me what I learned from him - and try to impart it to my own children - in his memory."
Oliver Stone was a fan, as well as Springsteen, whose bleak "Nebraska" album was inspired in part by "A People's History." The book was the basis of a 2007 documentary, "Profit Motive and the Whispering Wind," and even showed up on "The Sopranos," in the hand of Tony's son, A.J.
Zinn himself was an impressive-looking man, tall and rugged with wavy hair. An experienced public speaker, he was modest and engaging in person, more interested in persuasion than in confrontation.
Born in New York in 1922, Zinn was the son of Jewish immigrants who as a child lived in a rundown area in Brooklyn and responded strongly to the novels of Charles Dickens. At age 17, urged on by some young Communists in his neighborhood, he attended a political rally in Times Square.
"Suddenly, I heard the sirens sound, and I looked around and saw the policemen on horses galloping into the crowd and beating people. I couldn't believe that," he told the AP.
"And then I was hit. I turned around and I was knocked unconscious. I woke up sometime later in a doorway, with Times Square quiet again, eerie, dreamlike, as if nothing had transpired. I was ferociously indignant. ... It was a very shocking lesson for me."
War continued his education. Eager to help wipe out the Nazis, Zinn joined the Army Air Corps in 1943 and even persuaded the local draft board to let him mail his own induction notice. He flew missions throughout Europe, receiving an Air Medal, but he found himself questioning what it all meant. Back home, he gathered his medals and papers, put them in a folder and wrote on top: "Never again."
He attended New York University and Columbia University, where he received a doctorate in history. In 1956, he was offered the chairmanship of the history and social sciences department at Spelman College, an all-black women's school in then-segregated Atlanta.
During the civil rights movement, Zinn encouraged his students to request books from the segregated public libraries and helped coordinate sit-ins at downtown cafeterias. Zinn also published several articles, including a then-rare attack on the Kennedy administration for being too slow to protect blacks.
He was loved by students - among them a young Alice Walker, who later wrote "The Color Purple" - but not by administrators. In 1963, Spelman fired him for "insubordination." (Zinn was a critic of the school's non-participation in the civil rights movement.) His years at Boston University were marked by opposition to the Vietnam War and by feuds with the school's president, John Silber.
Zinn retired in 1988, spending his last day of class on the picket line with students in support of an on-campus nurses' strike. Over the years, he continued to lecture at schools and to appear at rallies and on picket lines.
"The happy thing about Howard was that in the last years he could gain satisfaction that his contributions were so impressive and recognized," Chomsky said. "He could hardly keep up with all the speaking invitations."
Besides "A People's History," Zinn wrote several books, including "The Southern Mystique," "LaGuardia in Congress" and the memoir, "You Can't Be Neutral on a Moving Train," the title of a 2004 documentary about Zinn that Damon narrated. He also wrote three plays.
One of Zinn's last public writings was a brief essay, published last week in The Nation, about the first year of the Obama administration.
"I've been searching hard for a highlight," he wrote, adding that he wasn't disappointed because he never expected a lot from Mr. Obama.
"I think people are dazzled by Obama's rhetoric, and that people ought to begin to understand that Obama is going to be a mediocre president - which means, in our time, a dangerous president - unless there is some national movement to push him in a better direction."
Zinn's longtime wife and collaborator, Roslyn, died in 2008. They had two children, Myla and Jeff.