Sousa was named as Montella's replacement on Sunday, 13 days after the Italian had been sacked with Fiorentina citing a breakdown in trust between club and coach.
Montella led Fiorentina to fourth in Serie A and a place in the Europa League, achievements Sousa is keen to build on in the coming campaign.
"I'm a big fan of Vincenzo Montella and his brand of football, so I’m honoured to be inheriting his team," said Sousa.
"I'll be similar to Montella in that I'll promote an attacking brand of football and try to create play rather than soak it up, through intensity and quality.
"But I want to put my stamp on the side, one of personality and courage.
"I'm here to work hard. Hopefully we can play enjoyable football, win games and achieve great things together.
"I've always made it clear that I was the right coach for this project and I'll do everything I can do repay that trust with the best results.
"From the start I've had great harmony with the club leadership. I saw in them characteristics similar to my own, huge ambition and a desire to do well."
Sousa also urged the club's supporters not to pre-judge him because of his time spent with rivals Juventus during his playing career.
He added: "I understand that some fans will remember me for my Juventus past, but I want you to start thinking about me for work done in Florence and for achieving excellent results."