"With tenacity and vision, Sargent Shriver built the promise of the Peace Corps into an American institution," Kerry said in a statement.
Within the family, Shriver was sometimes relied upon for the hardest tasks. When Jacqueline Kennedy needed the funeral arranged for her assassinated husband, she asked her brother-in-law.
"He was a man of giant love, energy, enthusiasm, and commitment," the Shriver family said in a statement. "He lived to make the world a more joyful, faithful, and compassionate place. He centered everything on his faith and his family. He worked on stages both large and small but in the end, he will be best known for his love of others."
In public, Shriver spoke warmly of his famous in-laws, but the private relationship was often tense.
According to Scott Stossel's "Sarge: The Life and Times of Sargent Shriver," an authorized 2004 biography, the ebullient and charismatic Shriver was a faithful man in a clan of womanizers, a sometimes giddy idealist labeled "the house Communist" by the family.
"He was never about personal accomplishments or personal celebrity except insofar as it helped him achieve his policy goals," Stossel said. "He thought of public service more broadly than just holding elective office."
After Kennedy's assassination in 1963, President Lyndon Johnson called upon Shriver to run another program which then existed only as a high-minded concept: the War on Poverty, a part of the new president's Great Society. Shriver's willingness to work for Johnson, whose dislike for the Kennedys was well-known, was seen as betrayal by some family members, according to Stossel.
Shriver's efforts in the Johnson administration demonstrated both the reach and frustrations of government programs: Head Start remains respected for offering early education for poor children, and Legal Services gave the poor an opportunity for better representation in court. But other Shriver initiatives suffered from bureaucracy, feuds with local officials and a struggle for funds as Johnson devoted more money to the Vietnam War.
In early 1968, with Shriver rumored to be on the verge of quitting, Johnson offered him the ambassadorship to France, a position he held for two years. He accepted it even though some family members wanted Shriver to support Sen. Robert Kennedy's presidential candidacy instead.
In Paris, Shriver won many French fans, but he left the post for a job in private business not long after Nixon took office in 1969.
Like always, he aspired to national office, but at times was thwarted by the family.
Hubert Humphrey considered him for his running mate in the 1968 election, but family resistance helped Humphrey change his mind.
When Shriver finally became a candidate, the results were disastrous: He was George McGovern's running mate in the 1972 election, but the Democrats lost in a landslide to President Richard M. Nixon.
McGovern recalled Tuesday how Shriver was the biggest morale booster on the campaign trail and even managed to raise his spirits the day after they lost so decisively.
"He came over and put an arm around me and said, 'Well, George we lost 49 states, but we didn't lose our souls,'" McGovern said in an interview from St. Augustine, Fla.
Four years later, Shriver's presidential campaign ended quickly, overrun by a then-little-known Georgia governor named Jimmy Carter.
His failures as a candidate left him with a reputation as a charming, but shallow salesman. (A "useless dingbat," wrote Hunter S. Thompson in his classic "Fear and Loathing: On the Campaign Trail '72").
When McGovern drafted him to replace Sen. Thomas Eagleton of Missouri on the ticket, Shriver was good humored that he had been McGovern's seventh pick — including Ted Kennedy. He named his campaign plane "Lucky 7."
After he dropped out of the 1976 campaign, he never again sought office. Instead, he helped run the Special Olympics and advocated an end to the nuclear arms race.
"Sargent Shriver helped Special Olympics break down barriers around the world and with his knowledge and expertise in foreign affairs and different cultures, helped turn Special Olympics into the international movement it is today," said Robert A. Johnson, president and CEO of the organization.
In 1994, Shriver received the Presidential Medal of Freedom, the nation's highest civilian honor, from President Bill Clinton.
"He leaves behind an astonishing legacy of people helped, lives transformed, and communities improved," the Clintons said. "Through his work and his passion, he helped build a better America and a more humane world."
His famous son-in-law, Schwarzenegger, called Shriver an inspiration.
"As someone who has always believed very strongly in the power of the body and the power of the mind and the power of will, Sargent taught me a new power: the power of the heart," said Schwarzenegger, who is married to Maria Shriver.
Besides Maria and Anthony, the Shrivers had three more sons — Robert, Timothy and Mark. Mark Shriver was elected to the Maryland House of Delegates in 1995 and ran unsuccessfully for Congress in 2002. They also had 19 grandchildren.
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