This is the first time soldiers have fought wildfires since 2006, and the call out shows how bad the problem has become.
About 95 fires have destroyed hundreds of homes, caused the evacuation of more than 1,000 people and burned 1.1 million acres in Oregon, Washington, Idaho, Montana, California, Nevada and Colorado, the NIFC said.
The soldiers will handle "quiet parts of the fire," NIFC spokesman Ken Frederick said
"That's important because it frees up our more experienced crews to handle more complex dangerous fire situations," he said. "So they (soldiers) could be mopping up, watching for and waiting to put out spot fires and digging fire line."
The soldiers will come from the 17th Field Artillery Brigade, 7th Infantry Division, at Joint Base Lewis-McChord in Washington, which has one of the worst wildfire problems.
Active duty soldiers have been used to fight wildfires 35 times since 1987, the NIFC said.
"The U.S. military has been a key partner in wildland firefighting for decades, and we greatly appreciate their willingness to provide us with soldiers to serve as firefighters," said Aitor Bidaburu, chairman of the National Multi-Agency Coordinating Group.
The military is also providing C-130s equipped to drop large quantities of fire retardant.
The NIFC fire alert level has hit the highest level -- last reached August 20, 2013, the NIFC said. Drought and scorching heat indicate a continued spread of fires
Here's a breakdown of what's happening in four of the worst-hit states:
A red flag warning is in effect for parts of California, where four years of drought have made it easy for flames to spread.
On Monday, 500 people were ordered to evacuate Santa Margarita, a small town in the central part of the state, said Bennet Milloy of CalFire. So far, no homes have been damaged by the fire that started Sunday and has burned 500 acres, he said.
One of the state's largest blazes, the Route Complex, had razed 28,401 acres and was 28% contained early Monday, authorities said.
The fire, which affected areas around Mad River, Dinsmore and Hyampom, started last month following a lightning storm.
Another blaze, the Mad River Complex, comprises seven fires
that started last month after a lightning storm hit northern California.
By early Monday, it had burned about 23,000 acres and was 65% contained. Two buildings were destroyed and five people injured. At least 19 fires were burning in the state.
In Fresno County, the Sheriff's Office ordered the evacuation of the Black Rock Reservoir area, including the popular Black Rock Campground.
In California's Angeles National Forest, 10 firefighters were evacuated with minor injuries.
In Montebello, a man was charged with unlawfully causing a fire after a blaze burned 370 acres on Monday, damaging 10 utility poles and leaving about 60 people without power, CNN affiliate KABC reported
Through August 8, there have been 4,382 fires that burned 117,960 acres, according to CalFire
. Through that date in 2014, there were 3,047 fires that burned 87,988 acres.
The Soda Fire has razed more than 265,000 acres in Owyhee County, in the southeast corner of the state. It was 25% contained with 860 people working to bring it under control, according to the national fire-tracking website InciWeb.
The cause of the fire is unknown.
The Lawyer Complex Fire near Kamiah, in northwest Idaho, has destroyed 50 homes, according to the state's Department of Lands.
So far, it is 15% contained, and includes the Old Greer, Kamiah Gulch, Lawyer 6 and Adams Grade fires, across a combined total of around 21,000 acres.
Mandatory evacuations and closures remain in place in some affected areas Monday.
Gov. Kate Brown has invoked the Emergency Conflagration Act in response to the Canyon Creek Complex Fire, which has burned more than 40,000 acres in eastern Oregon.
The declaration authorizes the state fire marshal to mobilize fire resources from around the state to protect homes. There are 14 major fires in Oregon, the governor said.
At least 26 homes have been destroyed in the Canyon Creek fire, the governor's office said, with 500 more homes threatened. About 300 people have evacuated. The fire started July 17 and is expected to grow 1,000-3,000 acres daily, depending on weather conditions, the governor's office said.
One homeowner said he was helpless to stop the fire.
"There was nothing we could do -- it was gone," Canyon Creek resident Dean Fox told CNN affiliate KTVZ
. "Embers were straight at me. We would have to keep hosing ourselves down, because it was so hot."
The fire was caused by lightning. About 475 fire personnel are trying to bring it under control.
Wind-pushed fires around Chelan and McNeil Canyon, a resort area in central Washington state, burned 38,793 acres and were 30% contained, according to InciWeb.
About 50 homes have been destroyed and 1,500 people are under evacuation orders.
The fires dealt a painful blow to the local economy when it destroyed the processing plant for Chelan Fruit Inc., the city's largest employer.
Dave Lewman, an employee, told CNN affiliate KIRO
about 1,000 people worked for the company.
"My grandfather is part of this operation. My dad, my brother used to be part of it," he told KIRO.
The fire also burned a winery and lumber yard, KIRO said.
Paul Smythe of Chelan lost almost everything when the fire destroyed his home in Chelan.
"I put everything I could in my car, got the animals and we bailed out," he told CNN affiliate KCPQ
The next day he drove by his house and "everything was gone. I'm trying not to think of all the stuff I lost. Not only does that house go out, cabins that have been in the family since 1935 are gone too."
The fires plunged 9,000 homes into darkness in Washington state on Sunday after flames engulfed utility poles outside Chelan.
On Monday, Chelan officials said they'd restored power to all but 600 customers in the Chelan Valley, according to CNN affiliate KXLY
Lightning strikes started the fires Friday morning
, said Jim Duck of the Central Washington Interagency Communication Center.
Eleven separate wildfires forced the closure of the Pacific Crest Trail between Glacier Pass and Holman Pass.
Over 1,000 people have fled Chelan County as the wildfires destroy homes
, CNN affiliate KPHO said.
The Washington Department of Natural Resources said
that as of August 11, there have been 751 fires on DNR-protected lands, with 628 of them caused by human activity.
By this time last year, the state had seen 565 fires, with 455 of those caused by humans.