Higuain, 25, passed a medical with the Serie A outfit on Wednesday and, according to club president Aurelio De Laurentiis, is now due to be officially presented as a Napoli player.
The Argentina international will join former PSV winger Dries Mertens and Real Madrid pair Jose Callejon and Raul Albiol in arriving at the club during the transfer window, with Liverpool goalkeeper Pepe Reina also poised to join on loan.
Having struggled for first-team chances at Real, Higuain will be looking to reignite his career in Naples - and Benitez is excited to work with the striker.
"We were looking for a quality player. We were looking for someone playing at the highest level," he told Corriere dello Sport.
"We have signed a player who comes from Real Madrid and we have signed a striker who has scored a hatful of goals and who will adapt very well to our system - an attacking system. We needed a player like this.
"We are all working together to ensure the players we want arrive. We have to sign players who will do well for Napoli for the next three or four years."
Napoli finished second in Serie A last term, with the goals of Edinson Cavani playing a big part in their success.
Cavani has since departed for Paris Saint-Germain, but Benitez is confident that they can improve on the previous campaign despite his exit.
"Players who come from clubs like Real, PSV and Liverpool can only do us good," he added.
"We have a great squad already, (former coach Walter) Mazzarri did great work, but we can move forward. For Napoli these signings represent a quantum leap."
