Overshadowed by his elder siblings, Teddy, as he was known to family and friends, grew up mostly in the New York City suburb of Bronxville, N.Y., and attended private boarding schools. He was expelled from Harvard during his freshman year after he asked a friend to take an exam for him.
After a two-year stint in the Army, Kennedy returned to earn degrees at Harvard and then the University of Virginia law school. He married Virginia Joan Bennett, known by her middle name, in 1958. The couple would have three children, Kara, Teddy Jr. and Patrick.
By the time he reached adulthood, tragedy had already claimed some of his siblings: eldest brother Joe Jr. was killed in World War II, sister Kathleen died in a plane crash, and another sister, Rosemary, who was mildly retarded, had to be institutionalized following a botched lobotomy.
But then the family hit its pinnacle in 1960, when John F. Kennedy became president.
His brother's ascension created a political opportunity, and Joe Kennedy decided he should take over JFK's Senate seat. Ted Kennedy was only 28 at the time -- two years short of the required age -- so a family friend was found to hold the temporary appointment.
In 1962, Ted Kennedy -- backed by his family money and the enthusiasm his name generated among Massachusetts' Catholics, was elected to the Senate.
In 1963, President John F. Kennedy was assassinated in Dallas. His brother Robert became the focus of the family's -- and much of the country's -- dreams.
Following the tragedy in Dallas, Robert and Ted Kennedy became closer than they had ever been as children.
"When I was working for Robert Kennedy, there was hardly a day in which the two of them didn't physically get together, I would say at least three or four times," said Frank Mankiewicz, who served as an aide to Robert Kennedy. "I mean, if, if Sen. Robert Kennedy wasn't in his office, and nobody knew where he was, chances are he was seeing Ted about something."
Five years later, while pursuing the Democratic presidential nomination in 1968 against Lyndon Johnson, Sen. Bobby Kennedy was shot and killed. That left Ted as the only surviving Kennedy son.
"He seriously contemplated getting out of politics after Robert's death," said Kennedy biographer Adam Clymer. "He thought, you know, it might just be too much. He might be too obviously the next target and all of that. But he decided to stick it out and as he said on more than one occasion, pick up a fallen standard."
Kennedy was seen by many as his brothers' heir, and perhaps he could have won the White House had he stepped into the presidential race then. But he didn't. And the very next year there occurred a tragedy that would forever block Ted Kennedy's presidential ambitions.
In July 1969, following a party on Martha's Vineyard, Kennedy drove off a bridge on the tiny Massachusetts island of Chappaquiddick. The car plunged into the water. Kennedy escaped, but his passenger did not.
Kennedy later said he dived into the water repeatedly in a vain attempt to save Mary Jo Kopechne, one of the "boiler room girls" who had worked on Bobby Kennedy's campaign. But Kopechne, 28, drowned, still trapped in the car.
Questions arose about how Kennedy had known Kopechne -- he denied any "private relationship," and Kopechne's parents also insisted there was no relationship -- and why he failed to report the accident for about nine hours.