The much-anticipated feature film adaptation of Jack Kerouac's influential 1957 novel boasts an all-star cast including Hedlund, Kirsten Dunst, Amy Adams and Kristen Stewart.
Speaking to Access Hollywood, the actor explained that completing work on the movie is particularly rewarding because executive producer Francis Ford Coppola spent three decades trying to get the project off the ground.
"I've been a fan [of On The Road] for such a long time - ever since high school. I signed on to the role four years ago so for the last four years, I've just been twiddling my thumbs, trying to get the [film] made," Hedlund remarked.
"I think there was a lot of anticipation from being on so long and just waiting for it to be [made]. To be able to get to [finally] play these characters, it's so phenomenal."
Earlier this week, Hedlund described his co-star Stewart as a "phenomenal" actress and predicted that audiences will be impressed by her performance in On The Road.
On The Road is expected to be released later this year.
> Stewart 'to kiss Garrett Hedlund in movie'
Watch Garrett Hedlund discuss On The Road below: