The 19-year-old striker joined the Toffees from Sheffield United for a four-year deal on deadline day and Unsworth believes he will seize his opportunity at a Premier League club by developing into a to quality player.
"He'll be a great acquisition to our very talented Under-23 group and I think he has the opportunity here now to kick on and play at the very highest level," Unsworth told the club's official website.
"He's joining a massive Club and this is an opportunity of a lifetime for him.
"To go from League One to the Premier League is a massive jump but he certainly has all of the attributes to make that jump, given time, hard work and the desire I know he has."
Calvert-Lewin, who was linked with Manchester United over the summer, spent time on loan with Northampton Town last season where he scored eight goals in 26 appearances for the League Two club.
He appeared twice for the Blades this season before making the move to Finch Farm where he will immediately link up with the Toffees U23 side.