Stoch finished 12.7 points in front of his nearest challenger, a one-sided margin when the ski jumping elite gather. He had the longest jump in both rounds of the final, sailing 105.5 and 103.5 meters.
He was one of a dozen jumpers who did not have to go through the pressure of qualifying on Saturday, but all those who had byes into the finals took a jump anyway and 10 competitors turned in a better effort than Stoch did.
When the jumping began for real on Sunday, no one could touch him. He finished with 278.0 points while Peter Prevc of Slovenia had 265.3. Anders Bardal of Norway was third with 264.1.
Stoch competed in the previous two Olympics and his best individual finish had been a 14th on the large hill in Vancouver.
Simon Ammann of Switzerland, the defending champion who was trying to win the event for the third time in four Olympics, wound up 17th.
The ski jumping was the last of the eight medal events contested on Sunday and those competitions were won by athletes from eight different nations.