Riddle, the 2011 world champion, last picked up a World Cup win in March 2008 but was victorious on his first start of this season almost five months after the opening round in New Zealand.
The 26-year-old was absent as the freestyle ski halfpipe World Cup kicked off in Cardrona in August but got the better of American duo Aaron Blunck and David Wise on their own snow.
Riddle's second run score of 91.2 gave him the victory with Blunck placing second with 87 while teammate Wise was third with 83.6, both landing better scores second time out.
Thomas Krief, who was second in Cardrona, was fifth this time to take the lead in the halfpipe World Cup standings with 125 points while Riddle goes straight in at joint-second.
He is level with another American Torin Yater-Wallace, absent from Copper Mountain, on 100 points with three more rounds of the season left in Park City, Sochi and Sierra Nevada.
Meanwhile in the women's halfpipe event American Maddie Bowman gave the home crowd something to cheer as she took the first World Cup victory of her career on only her third ever start.
Bowman made her debut on Copper Mountain in December 2011 finishing fourth before a second appearance on the circuit in Mammoth in March 2012 saw her finish third.
And Bowman, who turned 19 on Thursday, continued her improvement on the World Cup circuit as she returned to Colorado and posted a score of 84.6 to win the second round of the season.
Canada's Rosalind Groenewoud placed second with 79.2 while Bowman's American teammate Brita Sigourney completed the top three just 0.6 ahead of Virginie Faivre with 79.
Neither of the top three competed at round one in Cardrona with Manami Mitsuboshi, who was second in New Zealand, moving to the top of the standings after finishing 11th.
She holds a slender lead of four points ahead of winner in Cardrona Devin Logan and Bowman who both have 100 as does Ayana Onozuka who was sixth to add to her third in New Zealand.