Kane wrote his name into the history books in the 44th minute when he beat Gianluigi Donnarumma from the penalty spot for his 54th goal, overtaking previous record holder Wayne Rooney.
Declan Rice gave England an early lead when he scored from close range after Kane’s shot was blocked before the captain put memories of his penalty miss against France in the World Cup quarter-final in Qatar aside with an emphatic spot-kick.
Italy, whistled off at half-time in their first international in Naples for a decade, improved as England became sloppy.
Debutant Mateo Retegui was the beneficiary of poor work from Harry Maguire, whose failed attempt to close down the danger on the edge of the box allowed the Italians to shift the ball to the 23-year-old to drill an unerring finish past Jordan Pickford after 56 minutes.
England’s drop in performance was compounded by Luke Shaw’s second yellow card with 10 minutes left but they hung on for a vital win.