Jury president Jane Campion, the New Zealand filmmaker, handed the trophy to Ceylan, yesterday, who pipped 17 other contenders including David Cronenberg, Jean-Luc Godard and the Oscar-winning director of "The Artist", Michel Hazanavicius.
"Winter Sleep" drew rave reviews as a slow-burn domestic drama that mesmerised audiences despite its more than three-hour length.
Ceylan dedicated the award to the Turkish "youth who lost their lives" in violent anti-government protests that have rocked Turkey over the last year.
And Britain's Timothy Spall claimed the best actor prize for his role in "Mr. Turner", a lush historical biopic of 19th century painter JMW Turner by director Mike Leigh.
Having beaten a battle with cancer in the mid-1990s, Spall fought back tears as he thanked the jury, and God "to still be alive".
Bennett Miller scooped up the best director award for "Foxcatcher", a Hollywood film based on the real-life murder of an Olympic wrestler by multi-millionaire John du Pont.
"It's really something to be supported, and to have people who have faith in you, and to come out the other side," Miller said.
The runner-up Grand Prix went to Italian director Alice Rohrwacher, one of two women in competition, for her lyrical look at the rural life of a family of beekeepers, "The Wonders".
And the third-place Jury Prize was shared by the oldest and youngest filmmakers in the race, 25-year-old Xavier Dolan for his innovative drama "Mommy" and Godard, 83, with the 3D extravaganza "Goodbye to Language".