Montella was appointed the Viola coach in June after leading modest Catania to an impressive midtable finish in the 2011-12 Serie A season.
Della Valle believes that Montella can lead Fiorentina to success this term.
"Montella reminds me of early Cesare Prandelli," he enthused. "He has the same hunger and readiness to work, the same meticulous approach. You'll see as the days go by that he has been our best signing.
"I dream of hearing the Champions League theme tune again. We have been at the helm for 10 years and this is the turning point. We want to stay for a long time and never, ever buy a club that isn't Fiorentina.
"Our football history was born with Fiorentina and it'll die here too. When we were offered the chance to invest in Roma, we refused without a second thought."
Fiorentina will begin their Serie A season against Udinese in the weekend of August 25-26.