Pole-sitter Hamilton of McLaren gave up the lead only briefly during while winning the 53-lap Monza event for the first time in his career.
It was his third triumph of the season and 20th of his career. The performance boosted him within 37 points of F1 points leader Fernando Alonso of Ferrari, who finished third Sunday.
Hamilton came in 4.3 seconds ahead of Sauber's Sergio Perez, who matched his career-best finish.
Raikkonen used the result to move up to third in points (-38).