Canadian prodigy Summer McIntosh said she was "soaking up the moment" after the 17-year-old swimmer won her first Olympic gold medal in style on Monday.

World record-holder McIntosh produced a dominant 400m medley swim in Paris, clocking the fourth-fastest time ever.

She powered to the wall in 4mins 27.71secs, outpacing American pair Katie Grimes (4:33.40) and Emma Weyant (4:34.93).

It was the Toronto swimmer's second Paris medal after pipping Katie Ledecky to win silver behind Australian star Ariarne Titmus in the 400m freestyle.

"I'm just trying to soak up the moment as much as possible because obviously these moments only come around every four years. So just trying to make Team Canada proud," she said.

McIntosh's journey to the top began at the pandemic-delayed Tokyo 2020 Olympics, where she made her mark as a 14-year-old by coming fourth in the 200m freestyle behind winner Titmus.

Now at her second Games, she feels like a veteran and said her Japan experience helped her deal with the big occasions better.

"Every single time I get to race on the world stage I learn more and more about handling it, mentally and physically and emotionally, and trying not to get too high or too low, depending on my race results," she said.

Weyant praised the teenager for her composure and dedication.

"She set an impressive standard, for sure," said Weyant. "She is training with my old club team so she is in good hands. She continues to do impressive things."

The Canadian is also favourite in the 200m medley and a serious contender in the 200m butterfly.

"I just hope I try to inspire as many young kids as possible and I hope that they know that," said McIntosh.

"If I can do it, they can do it too.

"I was once in their shoes watching the Rio Olympics. And now that I'm here eight years later, I hope to inspire them as much as possible."