ABC News President David Westin told co-workers of Jennings’ death, writing, "For four decades, Peter has been our colleague, our friend, and our leader in so many ways. None of us will be the same without him.
Westin went on to described Jennings' struggle against cancer. "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," he wrote. :In the end, he was not."
Jennings is survived by his wife Kayce Freed, his two children, Elizabeth, 25, and Christopher, 23, and a sister, Sarah Jennings.
Jennings joined ABC News in 1964 and anchored the network's evening news from 1965 to 1967. At the end of that two-year period he asked to be reassigned as a reporter. He returned to the anchor desk as anchor and senior editor of "World News Tonight" in 1983.
As a reporter Jennings covered the Middle East, and the network credited his experience with giving ABC News perspective during 1991's Persian Gulf War as well as the current war in Iraq.
During continuous coverage of the September 11 terrorist attacks, Jennings anchored for more than 60 hours and was lauded for providing a steady voice during the crisis.
Along with Ted Brewster, Jennings wrote the News York Times bestseller The Century, which was also a series on ABC.
Jennings told viewers on April 5 that he had lung cancer. He did not returned to anchoring after that, but he was involved in making decisions about "World News Tonight." On his last birthday, July 29, co-workers had a banner flown over his home to let him know they missed him.