Stewart famously walked away from an Oscar-winning career at its peak to enlist in the as a private, nine months before the attack on Pearl Harbor.
In the upcoming biopic "Jimmy," Riggle, who is a retired U.S. Marine officer, plays Colonel Terrill, Stewart's squadron commander and mentor.
'BAND OF BROTHERS'
STARS IN THEIR PLACE DURING BOOT CAMP 'MUTINY', NEAL MCDONOUGH REVEALS
During a recent interview with Fox News Digital, the 56-year-old actor and comedian weighed in on whether modern celebrities would be willing to make the same wartime sacrifice as the late movie icon.
"I would be surprised if anybody made that same choice today, especially an actor of his status," Riggle said.
"He wanted to put on the uniform and serve where he could be used best," Riggle added. "And he was a pilot, so he put his hand in the air and went into harm's way. And I don't know if you'd see that today. I mean, I hope you would, but I would be surprised. "
Due to his fame, the military initially tried to keep Stewart, who was a licensed commercial pilot, stateside as a flight instructor and used him for publicity and March of Dimes promotional tours. However, Stewart repeatedly requested overseas combat duty, appealing to his superiors to let him fly rather than serve in public relations.
99-YEAR-OLD WWII VETERAN AWARDED PURPLE HEART AFTER WAITING MORE THAN 80 YEARS
Stewart's persistence eventually paid off, and he was sent to England in late 1943 with the 445th Bombardment Group. He went on to fly 20 official combat missions over Nazi-occupied Europe as a command pilot, squadron commander, and wing commander in B-24 Liberator heavy bombers.
REMEMBERING THE COLLEAGUES WE LOST: A VETERAN'S MEMORIAL DAY REFLECTION
Riggle noted that people may be unaware of the danger that Stewart willingly placed himself in while serving his country.
"I think Jimmy went through a lot harder service than most with the flying over Germany, dropping bombs, having to make those sorties under tremendous stress and loss of his peers," Riggle said.
"But I do think when you decide to serve your country, you're kind of writing a blank check with your life and limb and I think it takes a lot to do that, so I'm so proud of the way he served his country and came back and then found a way out of the darkness of PTSD," he added. "That was pretty amazing. "
As a commander, Stewart carried the immense burden of sending young men into brutal anti-aircraft fire and Luftwaffe attacks. During his service, Stewart witnessed heavy losses among his men and carried deep guilt over the lives lost under his command.
Biographers and historians have documented that Stewart suffered from severe psychological trauma, which caused digestive issues, insomnia, nightmares, shakes and sweats. Though Stewart's symptoms indicated that he was experiencing Post-Traumatic Stress Disorder, the formal was not established until 1980.
GARY SINISE SAYS HIS MONEY WOULD BE
‘MOVING A LOT FASTER OUT THE DOOR’
IF HE STILL LIVED IN CALIFORNIA
According to historians, portraying darker, more complex characters than in his pre-war Hollywood years enabled Stewart to process his trauma.
In the years following the war, Stewart enjoyed a successful career, built a family and continued his service in the Air Force Reserve for another two decades. Stewart died from a heart attack in 1997 at the age of 89.
The actor noted that his service gave a personal understanding of what it means to send young men into harm's way.
"I myself was a Lieutenant Colonel so I know what it is to be in charge of a group of people," he said. "I was a Marine but I know what it's like to be responsible and in charge and I know the weight of leadership. So I felt for all the characters in the movie that have that responsibility of leading men and making decisions that could affect their lives or end their lives. "
The actor later appeared in numerous sitcoms, including "New Girl," "Arrested Development," "The Office" and "Modern Family," in which he played Ty Burrell's character, Phil Dunphy's arch nemesis, Gil Thorpe.
He has also had roles in hit movies including "The Hangover," "Step Brothers," "The Other Guys," "Dumb and Dumber To" and "Let's Be Cops. "
Riggle told Fox News Digital that serving in the Marines gave him the qualities and mindset that he needed to succeed in Hollywood.
"Tenacity, don't quit, never give up, get up and try again," he said. "All those intangible lessons of mental toughness and fortitude, you need to have those if you're gonna be in Hollywood or any life in the arts, really. "
"Because people are going to reject you, people are gonna deny you, people are not gonna see it the way you see it," Riggle continued. "You've got to be able to take the blows and keep going forward. And I think that's what the Marines gave me with those intangibles. "
Riggle also said that his military background has helped keep fame and Hollywood success in perspective.
"I think it's great," Riggle added. "I think that it's very humbling and it's a good reminder. Get up and go do your job. "
Riggle shared that he considers his military service to be among his top life achievements.
"It's got to be right up there in the top three, next to my kids," he said.
"There should be some mention of it on my tombstone, let me put it that way," Riggle added with a laugh.
Riggle noted that while Hollywood is generally appreciative of former service members, he believes many civilians still harbor a fundamental misunderstanding about why men and women choose to enlist in the first place.
"I have felt that Hollywood is actually very respectful toward its veterans," Riggle said. "It's been really nice to see. But if there are misconceptions out there, I think some people, again, this is a general statement, but I think people might think that people who join the military, they do it because they don't have any other choices. "
"And that's simply not true," he continued. "They've got a tremendous amount of choices. And they choose to serve their country. "
"It's an all-volunteer force," he added. "No one's making them do anything. So the people that put their hand in the air have made that decision in their mind and that decision is to serve something bigger than themselves. And I think it's quite honorable. "
"Jimmy" depicts how Stewart was disillusioned and considering quitting acting when director Frank Capra (Max Casella) persuaded him to star as George Bailey in "It's a Wonderful Life" and how playing the role in the holiday classic enabled the actor to heal and reclaim his life.
Riggle told Fox News Digital that he was drawn to the project because it's a "great American story. "
GET ENTERTAINMENT SCOOP DELIVERED RIGHT TO YOUR EMAIL BY CLICKING HERE
"I think it's a patriotic story," Riggle said. "I think people know Jimmy, especially younger generations, know him from his acting. I really wanted people — or I'm glad to be part of the story that's being told, about his service to his country. "
"I hold it to high esteem,"he continued. "So I thought his journey was fantastic, it was amazing, and it was a ."
"I think he's a hero," Riggle added.
Riggle expressed his hope that audiences who watch "Jimmy" and may be unfamiliar with his military service may come to see him in a new light.
PUT YOUR ENTERTAINMENT KNOWLEDGE TO THE TEST AND SEE HOW YOU SCORE
"I hope they remember the man, Jimmy Stewart," Riggle said. "Most people just remember him from 'It's a Wonderful Life. ' Every Christmas they see him and they're like, ‘Oh yeah, I love this movie.’ And there's so much more to the man. "
CLICK HERE TO DOWNLOAD THE FOX NEWS APP
"And I hope they remember that there are people out there — we see so much news about the bad guys," he continued. "There's a lot more stories of good guys, you're just probably not seeing enough of them. And this is a story about a really great guy who did what he thought was right, followed his heart, followed his conscience, and did what he thought he needed to do, and we're all better for it. "