Having driven for Aston Martin in opening practice on Friday, de Vries was drafted in by Williams ahead of FP3 on Saturday when Alex Albon was taken ill and diagnosed with appendicitis.
The rookie qualified 13th and moved up five places on the grid thanks to penalties for other drivers to start eighth.
He eventually finished the race in ninth, logging two points on his debut.
Wolff said the result was what de Vries deserved after such a strong showing.
"He's just a good young man," Wolff said after the race. "He's not only fast, and has shown that in the junior categories, but he's also intelligent and a good team player.
"And that's why he deserved it today. I don't think that anyone else could have possibly done a better job in what he did.
"You're in an Aston Martin, you're driving around with the rake. And then you're being drafted at the last minute in a different car. You're beating your teammate by quite a margin.
"You're starting eighth, and you're finishing ninth. Niki [Lauda] would have taken his hat off as a driver."
Although de Vries has been closely associated with Mercedes as a Formula E racer and F1 reserve, he is not officially in the manufacturer's young driver programme or under any management deal in the way that George Russell and Esteban Ocon are.
However, Mercedes is still taking a keen interest in his progress.
"Nyck was an official Mercedes driver until we stopped Formula E a few weeks ago," said Wolff when asked by Autosport about the relationship.
"And he won the championship for us, our first world championship. So there isn't a more Mercedes driver.
"But we haven't got any management contract with him, nor have we got any influence on his career, nor are we taking any cut of his future earnings. We just know him very well.
"And we rate him, and I think that Nyck deserves to have a place in F1."
Lewis Hamilton, who knows de Vries well through their Mercedes associations, congratulated him in parc ferme after the Monza race.
"Incredibly happy for Nyck, I'm really proud of him," said Hamilton when asked by Motorsport.com about the rookie's performance.
"He's such a good lad, a good human. And he's been a good part of our team, helping and working with us. For Nyck to have jumped in and finished in the top 10, I think that's mega for your first race."
