While aboard an American Airlines flight, a man began complaining of chest pains and showed signs that he was suffering a heart attack.
After no one spoke up when the captain asked if there were any doctors on board, Manganaro stepped up.
"I was looking around. I'm like, 'Seriously, there's no doctor here? There's like 200 people and no doctor. Alright, here we go,'" Manganaro said. "[The man] was really pale, sweating through his shirt. He was wearing a white shirt; he was drenched in sweat, out of it – he wasn't feeling well."
Manganaro evaluated the passenger's symptoms and was patched through to a doctor on the ground.
"[I] talked to him on phone, told him, 'Gotta take the bird down; he needs to go to a hospital,'" Manganaro said.
>> Need something to lift your spirits? Read more uplifting news
The pilot made an emergency landing in Washington, D.C. so the passenger could be rushed to a hospital.
Veteran firefighters say that, despite Manganaro only being with the department for a short time, they couldn't be prouder of one of their rookies.
"He was a little out of his element, you know we go in as a team here," said Stoughton Fire Department Deputy Chief Scott Breen. "He was by himself on a plane, thrown into a position he was probably a little bit uncomfortable with, but he stepped up."
>> Read more trending news
Manganaro truly did step up and in a big way, saving a man's life.
"He [the passenger] sent me a message saying he's doing well, everything good on his end so it's really nice to hear he was very thankful and appreciative," Manganaro said.