Fresh out of graduate school, Priscilla Johnson McMillan worked briefly as a researcher for US Senator John F. Kennedy, whom she then befriended while he was hospitalized in the mid-1950s. A few years later, as a journalist in Moscow in 1959, she met and spent hours interviewing Lee Harvey Oswald, who had just defected to the Soviet Union.
Those disparate parts of her life intersected on Nov. 22, 1963, when she was in Harvard Square and heard someone say President Kennedy had been shot. A short time later, she recalled in a 1977 Globe interview, when she asked if anyone had been caught, a man “started to say Lee Harvey . . . and I gasped . . . and I filled in the last name: Oswald!”
Widely believed to be the only person who personally knew both JFK and his assassin, Mrs. McMillan died Wednesday in her Cambridge home. She was 92.
After Kennedy was slain, and Oswald murdered a couple of days later, she conducted extensive interviews with Marina Oswald, even living with the assassin’s widow for several months. She granted such access because Mrs. McMillan was fluent in Russian (Marina spoke little English), had known Lee, and had known JFK, who had been a source of fascination for the Oswalds.
In 1977, Mrs. McMillan published “Marina and Lee: The Tormented Love and Fatal Obsession Behind Lee Harvey Oswald’s Assassination of John F. Kennedy,” a deeply reported portrait of the couple and the time leading up to the fatal day.
“The clarity of her understanding, the effort and meticulous care of her work, and the extent of her research clarified a major event in American history,” said Thomas Powers, an author and Pulitzer Prize recipient in journalism who reviewed the book for The New York Times and subsequently became one of Mrs. McMillan’s close friends.
Powers said that among the scores of books about the assassination, many of which focus on conspiracy theories, hers endures because of the quality of the writing and of the writer — her attention to detail and her empathy.
“That’s why I put her on top of the tallest mountain. Few people ever do anything as significant as she did,” Powers said, adding that “she wrote, in my opinion, the most significant book about the assassination. It’s as fascinating and rich as a Russian novel.”
Powers, a founding publisher of Steerforth Press, which reissued “Marina and Lee” in 2013, said her “portrait of what actually happened, of course, won endless numbers of enemies for Priscilla,” including many who tried to claim she was part of a conspiracy and had worked for the CIA. (“No, I haven’t,” she told The Atlantic magazine in 2013.)
While “Marina and Lee” remains her most powerful work — “Other books about the Kennedy assassination are all smoke and no fire. ‘Marina and Lee’ burns,” Powers wrote in the Times — Mrs. McMillan published two other books.
Mrs. McMillan also was the English translator for “Twenty Letters to a Friend,” by Svetlana Alliluyeva, Joseph Stalin’s daughter, and she published hundreds of articles and book reviews in numerous publications, including the Globe, about assassinations, US-Soviet relations, and politics.
In 1961, she wrote an evocative essay for Harper’s magazine about attending the funeral and burial a year earlier of Boris Pasternak, the Russian writer and Nobel Prize recipient.
Joining the mourners who walked from Pasternak’s house to the grave, she watched as “the pallbearers emerged onto the porch and went down the steps with their burden. Parting obediently to make way, the crowd followed them over the lawn and out onto the winding dirt road that led to the churchyard. The open, papier-mâché coffin, with the wasted old body inside, could not have been very heavy. Nevertheless, at nearly every step of the way, young men sprang out of the crowd to help the six pallbearers carry Pasternak to his rest. Some, in their haste, dropped the flowers they had brought for the grave, so that a trail of flowers came to mark the path of the funeral procession.”
The third of four siblings, Priscilla Johnson was born in Glen Cove, N.Y., on July 19, 1928, and grew up in nearby Locust Valley, an affluent hamlet on Long Island.
Her father, Stuart H. Johnson, was a financier; her mother, Mary Eunice Clapp Johnson, was a homemaker.
Mrs. McMillan graduated from Bryn Mawr College in 1950, the first at the school to major in Russian language and literature. She also received a master’s in Russian studies from Radcliffe College.
In 1966, she married George McMillan, a journalist and author who wrote the “The Making of an Assassin,” about James Earl Ray, who murdered the Rev. Martin Luther King Jr.
The couple divorced in 1981, and he died in 1987.
For the remainder of her life, Mrs. McMillan’s Cambridge home became a way station for family members and friends.
“I think she’s the pioneer of the constructed family,” said her niece Holly-Katharine Johnson, who is writing a biography of Mrs. McMillan.
“Along with generations of graduate and undergraduate students, researchers and writers, who were her lodgers, almost every one of her nieces and nephews came for extended stays at 12 Hilliard Street at some point,” she added. “The door was literally always open. You might wander into her kitchen for a cup of coffee and find a couple of nuclear physicists and a civil rights attorney discussing the day’s headlines.”
Though a fall in the spring contributed to the decline in Mrs. McMillan’s health, she had “convened a democracy study group in the aftermath of the 2020 election that met by Zoom through the last half of the pandemic to evaluate American democratic institutions and potential reforms in the wake of the Trump presidency,” said another niece, Eunice Panetta, who is known as Nicie.
She added that her aunt also was “well-known for her endless supply of chocolate, cookies, and ice cream.”
The family will hold a service on Long Island for Mrs. McMillan, who leaves no immediate survivors, and a celebration of her life and work will be announced.
As the only person who had sat in rooms conversing one-on-one first with Kennedy, and then with Oswald, she had a unique perspective on each man, and in particular on the latter’s motivations.
Mrs. McMillan was convinced Oswald acted alone, and “oddly enough, Oswald liked John F. Kennedy. He approved his course in civil rights,” she wrote in the Times in 1970. “He followed the personal lives of several of the Kennedys. He knew a surprising amount about Kennedy the man.”
Recalling the 1959 night that she interviewed Oswald in a Moscow hotel room, she told The Atlantic that he had revealed to her his life goal: “I want to give the people of the United States something to think about.”
Though fascinated by Kennedy, Oswald saw him as a symbol of American capitalism. The assassination, Mrs. McMillan believed, was as much a crime of opportunity, because Oswald’s job was along JFK’s parade route in Dallas. “Presented with the target,” she said, “he thought he was fated to do it.”
As for those who wanted a more complex reason, she wrote in the Times that “it is easier to seek conspiracies outside than to look to the Oswald within.”
Bryan Marquard can be reached at email@example.com.