His wife Joan, mother of their now three children, suffered a miscarriage after the couple attended Kopechne's funeral, and she blamed it on Chappaquiddick.
Although the Kopechnes said publicly they had only received a small amount of money from Kennedy to use for the down payment on a house, his political opponents charged that the family had paid off the victims' family to keep quiet.
In the coming months, unanswered questions fed conspiracy theories, a slew of books on the topic and indignation in the national press.
A Newsweek cover story claimed Kennedy's friends had recently been "powerfully concerned with his indulgent drinking habits, his daredevil driving, and his ever-ready eye for a pretty face."
To many, those words would later ring true, when in 1991 Kennedy was present at a late-night hotel drinking binge with his nephew William Kennedy Smith, who was charged, but later acquitted of rape.
Press attention rippled across the island to the mainland, where Kopechne, the only daughter of a middle-class New Jersey family, was described by friends as "sweet" and a teetotaler.
Though no autopsy was ever done, her alcohol level was .09 percent, according to records at the time, about the equivalent of three to five drinks. Because of the 10-hour lag in reporting the accident, Kennedy's blood alcohol levels were never tested.
Americans were horrified when they learned that rescue workers found her body in the well of the back seat with her head held up, perhaps indicating that she had been alive for some time breathing in an air pocket.
The world press descended on the small, resort island. Tourists chipped away pieces of wood off Dyke Bridge and even stole bits of shattered glass from Kennedy's black Oldsmobile, which for days lay unprotected.
Gail Lance Huntoon was a 17-year-old working the front desk at her grandmother's hotel -- The Katama Shores on South Beach -- where Mary Jo Kopechne had a reservation to stay that ill-fated night.
"It was ridiculous," she told ABCNews.com. "Everything he said was a lie. People were really appalled because no charges were filed because he was a senator."
But today at 57, Lance Huntoon, whose family still lives on the island, views him differently.
"We were right there and it was so intense, but I really do have a softer opinion of him," she said. "He really tried to pay back in public service."
Many of those involved were unwilling to talk about the details of Chappaquiddick, including Sorensen, now 81, who helped craft the pivotal television address. But he lauded Kennedy's efforts to reinvent himself in its aftermath.
"He is a much more distinguished, decisive, solid leader in this country than he was prior to the 1969 accident," said Sorensen, who served as John F. Kennedy's speech writer and special counsel.
"Lots of people have tragic encounters with fate," he told ABCNews.com. "Some are ruined and never recover from it. Ted knew and accepted the fact that he would never succeed to the ambition of his brother that had first been planted in his mind."