"The Punisher" star was cast to play astronaut Dave Scott alongside Ryan Gosling in the movie, but before production started in November, 2017, Bernthal's then-two-year-old daughter had a seizure and went into a coma.
Jon rushed to be by her side and admits he was a mess during the scary situation.
However, his trauma nurse wife, Erin Angle, took charge of the situation and helped everyone stay calm.
"(She was) pouring love into our daughter every step of the way," he tells Men's Health. "People talk about bravery like fake macho bravery, but my wife didn't flinch. What I saw in my wife was courage and beauty unlike I'd ever seen."
Bernthal is currently filming the "Untitled Ford vs. Ferrari Project" biopic, in which he plays American automobile innovator Lee Iacocca, and while he insists he was eager to take on the role, he initially felt overwhelmed by it because production started two days after he wrapped filming on season two of Netflix series "The Punisher".
"One of my best friends, Sean Carrigan, came to set after my first week, and he saw how I was and he said, 'Hey, man, don't forget who the f**k you are'," he says. '"You're Henry Bernthal's father, you're Billy Bernthal's father, you're Adeline Bernthal's father. You are who you are, and you're what you've been through. Do not let this f**k you up.' I came back the next Monday a different man."