The Denmark striker scored in the Supercoppa Italiana semifinal win against AC Milan last night.
On-loan from Manchester United, Hojlund's deal includes a permanent option.
Asked about the centre-forward, Conte said after the 2-0 win: "As for Hojlund, he's a 22-year-old with significant potential, and the more he plays with us, the better he understands the things I ask of him.
"Today he was decisive. We're talking about a young player who can still grow a lot. We're holding on to him and hope to recover (Romelu) Lukaku as soon as possible.
"And then there's (Lorenzo) Lucca, who's also improving..."