Shriver died Tuesday at Suburban Hospital in Bethesda, Md., his family said in a statement. His health had been in decline since he was diagnosed with Alzheimer's disease in 2003.
By then, a lifetime as a public servant — a title he embraced tirelessly and unaffectedly — was behind him. "Serve, serve, serve" was Shriver's credo. "Because in the end, it will be the servants who save us all."
He started such innovative social programs as VISTA, a domestic version of the Peace Corps; Head Start, an enrichment program for low-income preschoolers; the Job Corps, to provide young people with vocational skills; and the aptly named Legal Services for the Poor.
Shriver was "one of the brightest lights of the greatest generation," President Obama said in a statement.
"Over the course of his long and distinguished career, Sarge came to embody the idea of public service," the president said. "Of his many enduring contributions, he will perhaps best be remembered as the founding director of the Peace Corps, helping make it possible for generations of Americans to serve as ambassadors of goodwill abroad."
From 1968 to 1970, Shriver served as U.S. ambassador to France. In 1972, he stepped in as Sen. George McGovern's Democratic presidential running mate after Sen. Thomas Eagleton bowed out. Four years later, Shriver briefly sought his party's presidential nomination.
Being a member of the Kennedy family put him at the apex of power but also thwarted his political ambitions. Shriver was considering running for governor of Illinois in 1960 when family patriarch Joseph P. Kennedy told Shriver that he was needed for John F. Kennedy's presidential campaign, official Shriver biographer Scott Stossel told The Times in 2004.
When President Johnson was considering Shriver as a running mate in 1964, another Kennedy — his wife's brother Robert — told him, "There's not going to be a Kennedy on the ticket. And if there were, it would be me," Stossel wrote in "Sarge: The Life and Times of Sargent Shriver" (2004).
Yet Shriver's record of public service and innovation was "unmatched by any contemporary leader in or out of government," Colman McCarthy wrote in 2002 in the National Catholic Reporter.
In the 1950s, Shriver was president of the Chicago Board of Education, and for decades he served on the board of the Special Olympics — the athletic games for the mentally disabled that was started in his backyard by his wife, Eunice Kennedy Shriver.
"All of these programs still exist, and they still change people's lives," Maria Shriver, who is married to former California Gov. Arnold Schwarzenegger, told the Associated Press in 2008.
On Tuesday, Schwarzenegger called his father-in-law's life "a blueprint for those of us who aspire to place the needs of others above our own."
Along with boundless energy and a commitment to those in need, Shriver was known for his relentless optimism. He also was a devout Catholic who attended Mass daily, carried a well-worn rosary and made no secret of his abiding faith.
His dedication to public service was matched only by his devotion to his family. Shriver spent seven years courting Eunice Mary Kennedy before she married him in 1953. They had been married for 56 years when she died at 88 in 2009.
Each of their five children followed their parents' example in pursuing public endeavors. Timothy Shriver, one of their four sons, said his father taught them "to locate our deepest aspirations in the public sphere."
Timothy, of Chevy Chase, Md., has been chairman of the Special Olympics since 1996. Eldest son Robert "Bobby" Shriver is a Santa Monica city councilman and film producer. Mark, who lives in Bethesda, was a member of the Maryland Legislature. Anthony, of Miami Beach, Fla., runs Best Buddies, which pairs college students with the mentally disabled. Maria, a former network news reporter who lives in Los Angeles, won two Emmys in 2009 for documentaries on Alzheimer's that she produced. One was based on a children's book she wrote, "Grandpa, Do You Know Who I Am?"
Robert Sargent Shriver was born Nov. 19, 1915, in Westminster, Md., to Robert and Hilda Shriver.