There’s much debate about the difference between Ivy and preppy, but it’s really quite simple: they occur at different points on a timeline.
For example, in 1964, when a spirited girl meets a handsome, reserved, all-American, clean-cut kind of guy who gets his clothing at Brooks Brothers, and simultaneously finds herself both attracted and repelled by him, she teasingly calls him “Ivy League.” Case in point, Barbara Eden and Peter Brown in “Ride The Wild Surf.”
And in 1970, after the fall of the Ivy League Look, when this same spirited girl meets the same all-American guy, she mockingly calls him “preppy.” Case in point, Ali MacGraw and Ryan O’Neal in “Love Story.”
So you see, the clothing is essentially the same. It’s just how women referred to the clothing — and the men who wore it. — CHRISTIAN CHENSVOLD