Hamilton took a record-extending 93rd career win at the Emilia Romagna Grand Prix as his Mercedes team clinched an unprecedented seventh successive Formula One constructors' title with four races to spare.
Hamilton, who had started on pole position in Sochi hoping for a 91st victory to equal Ferrari great Michael Schumacher's all-time record, finished third behind Red Bull's Max Verstappen.
Hamilton celebrated the 90th win of his Formula One career, one short of Michael Schumacher's all-time record, after a crazy crash-strewn Tuscan Grand Prix on Sunday that was twice stopped and re-started.
The news was expected, with champions Mercedes having made clear they intended to retain the 30-year-old Finn for a fifth successive season in what is likely to be an unchanged line-up.
Hamilton's 86th career victory, from his 90th pole position and collecting a bonus point at the end for fastest lap, left the six-time world champion five short of Michael Schumacher's all-time record of 91 wins.
Hamilton's Finnish teammate Valtteri Bottas, winner of last weekend's season-opener behind closed doors at the same Austrian circuit, finished a distant runner-up with his championship lead cut to six points.
The Mercedes and Ferrari drivers were back with their teams at the Red Bull Ring on Thursday ahead of this weekend's Styrian Grand Prix on the same track where they finished first and second respectively on Sunday.
Charles Leclerc finished a surprise second for Ferrari with McLaren's Lando Norris celebrating a first podium after a time penalty dropped Mercedes' six-time world champion Lewis Hamilton to fourth.
The 34-year-old Briton finished second at the Circuit of the Americas to become only the second driver after retired Ferrari great and seven-times champion Michael Schumacher to win six titles.
The result also left only Bottas capable of challenging Hamilton, who saw his lead narrow to 64 points, in the overall standings.