The suave, Canadian-born broadcaster delivered the news to Americans each night in five separate decades. He was there for every big story, be it war or weather.
Jennings, who announced in April that he had lung cancer, died Sunday at his New York home, ABC News President David Westin (search) said in a statement. He was 67.
"Peter has been our colleague, our friend, and our leader in so many ways," Westin said. "None of us will be the same without him."
With Tom Brokaw and Dan Rather (search), Jennings was part of a triumvirate that dominated network news for more than two decades, through the birth of cable news and the Internet. His smooth delivery and years of international reporting experience made him particularly popular among urban dwellers.
Jennings dominated the ratings from the late 1980s to the mid-'90s, when Brokaw surpassed him. He remained a Canadian until 2003, when he became a U.S. citizen, saying it had nothing to do with his politics — he did it for his family.
"He was a warm and loving and surprisingly sentimental man," said Ted Koppel, a friend and fellow anchor.
Jennings deeply regretted dropping out of high school, and he would have wanted that lesson passed along, Koppel said. He made up for it by becoming a student of the world, studying cultures and their people for the rest of his life.
"No one could ad lib like Peter," said Barbara Walters, also a friend and fellow anchor. "Sometimes he drove me crazy because he knew every detail. .... He just died much too young."
Jennings was wherever the big story was. He logged more than 60 hours on the air during the week of the Sept. 11, 2001, terrorist attacks, offering a soothing sense of continuity during a troubled time.
"There are a lot of people who think our job is to reassure the public every night that their home, their community and their nation is safe," he told author Jeff Alan. "I don't subscribe to that at all. I subscribe to leaving people with essentially — sorry it's a cliche — a rough draft of history. Some days it's reassuring, some days it's absolutely destructive."
Jennings' announcement four months ago that the longtime smoker would begin treatment for lung cancer came as a shock.
"I will continue to do the broadcast," he said, his voice husky, in a taped message that night. "On good days, my voice will not always be like this."
Although Jennings occasionally came to the office between chemotherapy treatments, he never again appeared on air.
"He knew that it was an uphill struggle. But he faced it with realism, courage, and a firm hope that he would be one of the fortunate ones," Westin said. "In the end, he was not."
Broadcasting was the family business for Jennings. His father, Charles Jennings, was the first person to anchor a nightly national news program in Canada and later became head of the Canadian Broadcasting Corp.'s news division. A picture of his father was displayed prominently in Jennings' office off ABC's newsroom.
Charles Jennings' son had a Saturday morning radio show in Ottawa at age 9. Jennings never completed high school or college, and began his career as a news reporter at a radio station in Brockton, Ontario. He quickly earned an anchor job at Canadian Television.
Sent south to cover the Democratic national convention in 1964, the handsome, dashing correspondent was noticed by ABC's news president. Jennings was offered a reporting job and left Canada for New York.
As the third-place news network, ABC figured its only chance was to go after young viewers. Jennings was picked to anchor the evening news and debuted on Feb. 1, 1965. He was 26.
"It was a little ridiculous when you think about it," Jennings told author Barbara Matusow. "A twenty-six-year-old trying to compete with Cronkite, Huntley and Brinkley. I was simply unqualified."
Critics savaged him as a pretty face unfit for the promotion. Using the Canadian pronunciations for some words and once misidentifying the Marine Corps' anthem as "Anchors Aweigh" didn't help his reputation. The experiment ended three years later.
He later described the humbling experience as an opportunity, "because I was obliged to figure out who I was and what I really wanted to be."
Assigned as a foreign correspondent, Jennings thrived. He established an ABC News bureau in Beirut, and became an expert on the Middle East. He won a Peabody Award for a 1974 profile of Egyptian President Anwar Sadat.
On the scene at the Munich Olympics in 1972, Jennings was perfectly placed to cover the hostage-taking of Israeli athletes by an Arab terrorist group. He and a crew hid in the athletes' quarters for a close-in view of the drama.
Jennings returned to the evening news a decade after his unceremonious departure. In 1978, ABC renamed its broadcast "World News Tonight," and instituted a three-person anchor team: Frank Reynolds based in Washington, Max Robinson from Chicago and Jennings, by then ABC's chief foreign correspondent, from London.
Following Reynolds' death from cancer, ABC abandoned the multi-anchor format and Jennings became sole anchor on Sept. 5, 1983.
Starting in 1986, Jennings began a decade on top of the ratings. His international experience served him well explaining stories like the collapse of European communism, the first Gulf War and the terrorist bombing of an airplane over Lockerbie, Scotland. He took pride that "World News Tonight," as its name suggested, took a more worldly view than its rivals. Fans responded to his smart, controlled style.
"When it's clearly an emotional experience for the audience, the anchor should not add his or her emotional layers," Jennings said in an interview with the Star Tribune in Minneapolis.
Two-thirds of local broadcasters responding to a 1993 survey by Broadcasting & Cable magazine said Jennings was the best network news anchor. Washington Journalism Review named him anchor of the year three straight years.
With Americans looking more inward in the mid to late-1990s, NBC's Tom Brokaw surpassed Jennings in the ratings. ABC was still a close No. 2, however. When Brokaw stepped down in November 2004, followed shortly by Rather, ABC began an advertising campaign stressing Jennings' experience — an ironic twist given how his ABC News career began.
But ABC was never able to learn whether Jennings could take advantage of his role as an elder statesman; his cancer diagnosis came only a month after Rather left the anchor chair.
Jennings was proud of his Canadian citizenship, although it was occasionally a sore point with some critics. When Jennings spoke at the dedication of a museum celebrating the Constitution in 2003, Supreme Court Justice Antonin Scalia told him, "not bad for a Canadian."
Jennings whispered back his secret: He had just passed a test earning him dual citizenship in the United States.
"My decision to do this has nothing to do with politics," Jennings told The Associated Press at the time. "It has nothing to do with my profession. It has everything to do with my family."
Restlessly curious, Jennings pushed ABC News to use the turn of the century for a massive historical study. He co-wrote a book, "The Century," with Todd Brewster and anchored a marathon 25-hour special ending Jan. 1, 2000. Jennings and Brewster also traveled the backroads to write "In Search of America."
Jennings also led a documentary team at ABC News, which struck a chord in 2000 with the high-rated spiritual special "The Search for Jesus."
"I have never spent a day in my adult life where I didn't learn something," Jennings told the Saturday Evening Post. "And if there is a born-again quality to me, that's it."
Like Rather and Brokaw, Jennings wasn't entirely comfortable stuck to a studio. He traveled around the world to cover stories and, when he didn't journey to Asia to cover the aftermath of the tsunami less than four months before his cancer diagnosis, it was noticed.
He is survived by his wife, Kayce Freed, and his two children, Elizabeth, 25, and Christopher, 23.