The Hunger Games director has written a short piece for new issue of The Hollywood Reporter, recalling what a pleasure it was to work with the Fast & Furious star.
Ross writes, "When I think back on Paul, I can't help smiling... He came in the door with that huge winning smile (like he'd already gotten some big cosmic joke), and it wasn't until after a few minutes of chatting that I noticed the women in the room were speechless. Not just speechless, frozen - literally agape."
The director recalls the penniless actor returning to his casting office to reclaim his acting headshots after his audition for Pleasantville - and admits he has never regretted hiring him at 23.
He adds, "The audition was wonderful, and I decided to cast him. But before I could even call him to tell him he had the part, Paul showed up in the casting office. He was broke back then - really broke - and he was coming back to pick up his eight-by-10 headshots. He figured if we were all done with them, he could save the money on having new ones printed.
"When I told him I wanted to cast him, Paul didn't believe me at first."
And Ross urges Walker's fans who really want to see the actor at his best to rewatch Pleasantville: "You will see a guy fully committed to a character that he was having a ball with. There were several takes when playing this guy - this benighted, naive, unconscious high school hero - literally cracked him up.
"He delighted me every day. He was boyish, exuberant, happy and surprisingly wise. In one pivotal scene in the movie, when the film begins to morph into something darker - when all the emotions that have been unleashed on the town begin to be expressed - Paul came up to me before I could come up to him... (and said), 'I think I'm different here. I think this is the moment where I stop smiling'. He was right, of course. It was subtle, but it was the turning point in the film.
"I just know that when I look back on him, I will never stop smiling."
Walker died in a car crash on Saturday.