Henry Winkler is applauding legendary producer Norman Lear for making an enormous impact on America's TV landscape, and even bigger ... on American society.

Being a TV icon himself, "The Fonz" joined us Wednesday on "TMZ Live," and admitted it's not easy to find the right words to describe someone like Norman, who accomplished so much in life, with "grace, intelligence, and fun."

Henry shared an anecdote about Norman's 101st birthday party, where someone asked how he felt about reaching that age, and he wittily responded ... "Not as good as I'll be at 102!"

His point being, Norman -- who passed away Tuesday -- was always a forward-thinking guy, who used his art to help Americans see the best and worst in themselves ... tackling topics like homosexuality, racism, the Vietnam War and women's rights -- which had never been done before on TV.

As for Henry ... well, his memoir, "Being Henry: The Fonz ... and Beyond," is approaching one month on the New York Times Bestseller list -- and after 50 years in showbiz, he told us why he's just now discovering his true self.