The 20-year-old put down the two highest scoring runs of the final. Her second, which produced her winning score, included two cleanly executed 900 spins and a backwards 700, combinations that none of her rivals could match.
Hers victory completed an American sweep of the gold medals in the debut of ski halfpipe, after David Wise won the men's competition.
“The way I've gotten here is taking it one day and one competition at a time and having absolutely as much fun as I could, and hey, it worked out,” said Bowman.
For Martinod, 29, the motivation to succeed was a little different. “I wanted to show my daughter that the way to achieve your goals is to focus on them,” she explained.
“She needs to understand why I am busy doing press-ups while she is watching her cartoons.”
Meanwhile, the 25-year-old Onozuka, who kept world champion Virginie Faivre of Switzerland off the podium, was in a state of shock at winning bronze.
“I can't believe that I have got a third place. I was nervous the whole day and I couldn't concentrate, but I tried not to worry about it.
“She’s got it all”
Bowman’s fellow American, Brita Sigourney, who finished sixth, paid her team-mate the ultimate tribute.
“[Maddie] said that she wanted me to win and that she's so proud of me,” revealed Sigourney, who had skied straight into her fellow American’s arms after botching her second run of the final.
“I told her to shut up because she deserves this more than anyone. Her’s was the most technical run out of any girl skiing. It's more technical than any run any girl has done all year, plus it's got amplitude and style, she's just got it all.”