Morimoto spent five years at Catania before moving to Novara last year.
Catania president Nino Pulvirenti says, “we have always believed in Morimoto and we welcome him back with open arms.”
The Japanese striker signed for Catania in 2006, initially on a one-year loan deal, from Tokyo Verdy 1969. The move was made permanent at the end of the season.
Morimoto, who turned 24 in May, was Novara's best player last season but could not prevent the side from finishing 19th in the standings and being relegated to Serie B.