The Canadian suffered a concussion in the season-opener at Cardrona, New Zealand in August, and finished third at last weekend's Winter X Games behind world champion Kelly Sildaru in her first event back.
She returned to the top of the podium at Mammoth Mountain, California, with her first run proving sufficient to retain the title after her win over Sildaru last year.
In the men's competition, Aaron Blunck went one better than his second place at Aspen last weekend with three 90-plus runs in one of the finest series in freeski halfpipe history.
Sharpe back with a bang
In a high-quality first round, China's Li Fanghui - who took silver behind team-mate Gu Ailing Eileen at the Lausanne 2020 Winter Youth Olympics - went into the lead with a score of 85.00 before X Games silver medallist Rachael Karker - who was second in qualification - scored 88.00 to take the lead.
The top qualifier was Karker's fellow Canadian Sharpe, and she put down an excellent run capped by a big left side 1080 tail jump to post 90.00 which would not be beaten.
Sharpe said afterwards, "I just wanted to come out and have fun. But I’m so competitive that I can’t just come out here to have fun.
"I practised a tonne leading up to the X Games and then I got third which, honestly, is the first time I’ve ever felt OK with a third.
"I’m just happy to come out and I'm happy to be on top but that everybody's OK. It's the most beautiful day we've ever had in Mammoth for a final." - Cassie Sharpe
Russia's Valeriya Demidova showed why she is top of the World Cup standings with a fine second run, scoring 89.00 to go into second place.
Lausanne 2020 bronze medallist Hanna Faulhaber was seventh.
Blunck in a class of his own
After a disappointing seventh at the Aspen X Games, Noah Bowman set a stern target with 88.60 in his first run.
But it was the Aaron Blunck show after that.
The American took the lead with 94.20, improved to 96.20 in his second run and then went even better on his third and final run in a stellar series.
Lyman Currier pulled out his best run at the end, scoring 88.20 to edge out 2016 Youth Olympic gold medallist Birk Irving for the final spot on he podium.
It was a final to forget for double Olympic champion David Wise who fell early in his first and third runs and only scored 35.80 on his second run to finish in 10th and last place.
But all the focus was on Blunck who went clear of Bowman at the top of the World Cup standings.
Speaking afterwards in the run-off area, Blunck said, "I'm honestly lost for words, I am so stoked. This is one of the best days that we've ever gotten to compete in and I think everyone was just vibing with the sun.
"After that first run I was so nervous and I landed it and I was, 'You can only go up from here. You've got a solid run down. Let's just keep going, let's keep vibing.' And I just kept feeling it more and more so I really just couldn't be more stoked to finish off today with the runs that I did."