For reigning champion Sebastian Vettel, finishing second from pole was a personal disappointment, but not enough to prevent his Red Bull team from winning the constructors title for the third successive season.
Fernando Alonso of Ferrari finished third after starting seventh on the grid -- thanks to his team's pragmatic decision to break the gearbox seal on teammate Felipe Massa's car.
That podium finish ensured that the title battle will go down to the wire at next weekend's Brazilian Grand Prix in Sao Paulo.
Vettel goes to Interlagos with a lead of 13 points. Vettel has 273 points and Alonso 260.
Hamilton, who started second on the grid, made the most of his superior outright speed to pass Vettel on lap 42 of the 56-laps race and claim the 21st victory of his career.
The 27-year-old Briton, who leaves McLaren for Mercedes next year, was intent on delivering another win for the team before his departure and did so with elan as he seized his fourth win this year.
Massa, who was demoted five places to 11th on the grid because of Ferrari's strategic move which elevated Alonso one place to the clean part of the grid, finished a superb fourth ahead of Jenson Button in the second McLaren.
Kimi Raikkonen, winner of the Abu Dhabi Grand Prix two weeks ago, came home sixth ahead of Lotus team-mate Romain Grosjean, Nico Hulkenberg of Force India, Pastor Maldonado and his Williams team-mate Bruno Senna.