Linguistics, obviously.
Philosophers love him, because he always gives them an argument, and that's all they really care about.
There probably wouldn't even be cognitive science without Chomsky. And psychology is still responding to Chomsky's nuking of behaviorism in the 1950's.
So, there's a lot there, but admittedly most of it is for politics.
Just look at his Wikipedia entry. He finished his dissertation in 1955, starting teaching at MIT the same year, and continued to publish seminal linguistic works over the next 12 years. That's all before he gained any notoriety whatsoever as a critic of the U.S.'s role in the Vietnam War.
Manufacturing Consent was published in 1988!
Additionally, I strongly doubt Chomsky had any "name recognition" all the way through to the late 90s. Outside of a single episode of Firing Line, where would the general public have heard his views?
That said, as a computer science student I learned of his hierarchy of formal languages before I learned of his politics.
A formal theory of finite automatons, both determinitic and non-determinitics, is due to Michael Rabin & Dana Scott, for which they received a Turing prize. 1959.
No offense but your question is terribly ignorant, naive, and biased. Just spend a few seconds reading his Wikipedia article.