"It was a movie that, it was a classic, almost an immediate classic, and people went to see it and people came back to the theater and saw movies again, so it was quite remarkable," Hopper told ABC News entertainment correspondent Bill Diehl.
But Hopper's next project, 1971's "The Last Movie," was considered an expensive, drug-addled flop.
Before "Easy Rider," Hopper had acted alongside James Dean in "Rebel Without a Cause" and "Giant."
He received two Oscar nominations during his career, one for writing "Easy Rider" along with co-star Peter Fonda and Terry Southern, and the other for playing an alcoholic high-school basketball coach in the 1986 film "Hoosiers."
"It's just inspirational," Hopper once said of "Hoosiers" in an American Film Institute interview. "I have so many coaches come to me and so many players. ... They're all watching 'Hoosiers' suddenly. And it's the first time in my career, because I've played so many villains, that little kids come up to me and call me coach."
Hopper's more recent work included a major role in the TV series "Crash."
Asked in a 1990 interview about being called a Hollywood legend, Hopper told Diehl, "I guess if I really stop and think about it, which I try not to do, I guess I've known a lot of people. I've been very lucky to be in a lot of places. And I guess there's an old adage: 'If you just live long enough ...'"
ABC News Radio contributed to this report.