The man, whose name was not immediately released, became the first casualty of a huge fire near the beloved tourist town of Jasper in Alberta province. Last year's historically bad fire season claimed eight lives.
The victim, a Calgary native, suffered a serious injury Saturday afternoon when struck by a falling tree "while fighting an active fire northeast of Jasper," said a statement from the Royal Canadian Mounted Police (RCMP).
He was transported, first by helicopter and then by air ambulance, to a hospital but was later declared dead, said Parks Canada, the federal agency that manages the national parks.
"Every single person responding to the Jasper Wildfire Complex is in mourning today for our friend and colleague," said a joint statement from Parks Canada and the town of Jasper posted on Facebook.
"The wildland fire community is small and every loss deeply impacts us all."
Prime Minister Justin Trudeau said he was "heartbroken" by the loss, adding on social media platform X that "he served Albertans with unwavering bravery, and his loss is deeply felt."
Several firefighting units paid homage to their fallen comrade Sunday morning in a vigil in the nearby town of Hinton.
Provincial authorities said they were investigating the circumstances surrounding the death.
Some 700 firefighters, including several from other countries, are now fighting the vast wildfire, which has burned some 34,000 hectares (84,000 acres).
Ignited two weeks ago by lightning in a region enduring severe drought, the fire destroyed a substantial part of the tourist city of Jasper, known as the jewel of a naturally beautiful region that draws 2.5 million tourists a year.
Still out of control, it is the largest fire to hit Jasper National Park in 100 years -- and it could burn for months more, the authorities say.
On Friday, the highway serving the city of Jasper was partly reopened to traffic, and authorities allowed evacuated residents traveling on chartered buses to come inspect their homes, conditions permitting.
No date has been announced for a full return to the city.
Last year saw a catastrophic number of wildfires in Canada, with 15 million hectares burned and more than 200,000 people evacuated.
