The 23-year-old United States international signed a four-year deal with the Black Cats on Tuesday as he completed his move to the Stadium of Light from Dutch side AZ Alkmaar.
Altidore scored only once in 28 Premier League appearances for Hull City during a loan spell in 2009/10 but he netted 31 times in all competitions for AZ last season.
He has already joined up with his new Sunderland team-mates at their pre-season training camp in Italy and featured in the second half of a practice match on Wednesday.
Di Canio told the club's official website: "Altidore is one of the top strikers in Europe. He only joined us on Tuesday but I'm very happy, curious and excited because I have a very good attacking side at the moment.
"I'm really pleased because a new arrival can benefit the squad and also individuals because there is competition up front."