In the build-up to the announcement, doubts had emerged around Vettel due to option clauses on both sides in the multi-year deal he signed upon initially joining the team at the end of last year.
With Vettel now on board, Szafnauer has highlighted why the four-time F1 champion is continuing.
"He is a very principled person, a man of high integrity, which personally I like," said Szafnauer.
"He's not afraid to speak his mind, which I also like.
"He went and did litter picking at Silverstone, which I sometimes do in Oxford myself because I don't like litter.
"So the fact he spent a couple of hours picking up litter in the grandstand, I like that, too.
"He is a generally good guy, he cares about people, and he now cares about the environment, with his litter picking, no plastics.
"So he is a good guy, and we like him.
"On the driving side, he works super hard and he has high expectations of both himself and the team."
As far as Szafnauer is concerned, Vettel remaining with Aston Martin was always on the cards, to such an extent no conversations were had with any other drivers
Szafnauer added: "If there was any doubt in our minds, in July, when all these other people were thinking 'Should I go to Williams or Alfa Romeo', all that kind of stuff, we would have been having those conversations. But we didn't."
GPFans is a multi-platform, multi-language brand dedicated to Formula One coverage. We bring you all the ins and outs of the sport, 24/7, everything from up-to-the-minute news and features to the latest viral stories and clips.
We believe that a new generation of exciting, outspoken drivers will make F1 more popular than ever before, and we want to give our users access to as much of their heroes as possible, on and off the track. From Lewis Hamilton to Max Verstappen, Daniel Ricciardo to Sebastian Vettel, we provide in-depth analysis of every every Grand Prix in the season, from Australia to Abu Dhabi.
With Formula One under the new ownership of Liberty Media, how the sport is being covered is evolving, and GPFans will look to be at the heart of this progression into new media, as one of the fastest-growing sites covering the king of motorsports.