Through prep school at Choate, his years at Harvard, and his young adulthood, JFK could be seen in shirts with button-down collars, the epitome of the Ivy League look.
At the supposed urging of his brother-in-law Peter Lawford and perhaps Jackie, the abandoned the button-down in favor of short straight collared shirts.
In fact, as he progressed through the Senate and into the Presidency, he tried to get his brother Bobby to drop the buttondown as well. He is quoted in Life magazine as saying of RFK,
“He’s still wearing buttondown shirts; they went out at least three years ago.”
He told his Navy buddy and close friend Paul “Red” Fay that his buttondown collars were too “Ivy League.”