Marion Fahnestock, nicknamed Mimi, said it was a “huge relief” to finally confess to her clandestine relationship with the former US President.
“I was 19-years-old, a very young, very naive, very innocent girl,” she told the New York Daily News.
Details of the affair emerged this week after a sealed portion of a 1964 interview with a former Kennedy press aide was made public in a new biography about the former leader.
The teenager was first invited to the White House in 1961 to interview Jacqueline Kennedy, who had been at her exclusive girls’ boarding school in Connecticut.
She never met the First Lady but caught the eye of her husband who had recently become the youngest elected US President.
A year later she returned to the White House as an intern and soon became Kennedy’s lover.
Historian Robert Dallek, author of the Kennedy biography An Unfinished Life, said Mrs Fahnestock was taken on despite her lack of office skills.
“Apparently, her only skill was to provide sexual release for JFK on those trips and maybe in the White House,” he said.
She was invited to White House pool parties and flown on US Air Force jets to secret liaisons with the president at resorts and summit meetings. White House aides once caught her hiding on the floor of a limousine in Kennedy’s entourage in the Bahamas moments after the president had left.
Mrs Fahnestock, a tall, slim woman with short blonde hair, declined to talk about Kennedy, saying only: “I think the world knows what he was like.”
She worked at the White House for two summers before returning to university in the autumn of 1963, just a few weeks before Kennedy was assassinated. After graduation she married and had a family but never told anyone of her famous former lover.
Now a divorced grandmother of four, she lives in Manhattan’s smart Upper East Side and works at the Fifth Avenue Presbyterian Church.
She said she was pleased the story had finally emerged.
“The gift for me is that this allowed me to tell my two married daughters a secret that I’ve been holding for 41 years.”