The centre-back earlier in August moved to the Premier League from Wolfsburg in a deal worth around £43million, and has immediately established himself as first-choice alongside vice-captain Cristian Romero.
Spurs have started the season well, showing tantalising attacking threat in a draw away at Brentford and a home victory over Manchester United, and Van de Van says Postecoglou's personal approach and tactical style of play convinced him to join.
"I spoke with the manager, I think that's the most important part to make your decision," he told talkSPORT. "Of course you can talk with people from the club like the director, but he's not going to train you on the pitch, it's the trainer who has to make you better.
"You have to love his style of play, how he wants to play, you have to love it, because if you don't get the vibe, the feeling, the system I want to play, then it's not going to work. So I talked with the trainer and everything in the meeting went well and I love the way of playing, so that made a really huge decision for me to go to Tottenham."
He added: "He's a lovely guy. He is so good for all of us, he's quiet, but he's straight in with what he wants. He is clear, everything is clear for everyone in the dressing room and everyone in the team knows what he has to do and what he is expecting from us.
"He's a sweet guy - a lovely guy - but he's straight and he knows what he wants to be and what he expects from us in his way of playing. He has a good vibe with everyone, he has a good relationship with everyone and I think all of the team loves him and we feel like one family and I think that's really important."
Postecoglou arrived at Spurs from Celtic, spending three years in Scotland and winning eight trophies with his final match wrapping up a remarkable Treble.
Van de Ven believes Postecoglou could replicate his trophy haul in north London, adding: "That's a possibility.
"I think how we play now, every player in the team loves the way of playing under him, the way he thinks about football. We feel each other and we know what he wants and we know what he expects from us.
"So we do what he wants, and I think he also looks at how we think about it, so it's not only from one way, but from both ways, and I think that will help the team and the manager also to develop everyone."