The infant's 13-year-old mother gave birth while in the bathroom, and her 12-year-old sister called 911 around 4:20 p.m., the Detroit News reported.
Detroit Deputy Fire Commissioner Dave Fornell said first responders found the mother unconscious on the toilet and the baby on the floor, wrapped in a blanket and gasping for breath, WXYZ reported.
"Every 30 seconds, there was a little gasp," Sgt. Tom Suchora told WJBK. "When I put my finger in its mouth to try clearing its airway, it actually gagged a little bit -- so I knew there was a chance."
The infant and his mother were stabilized and taken to an area hospital, WXYZ reported.
"The first responders saved the kid's life, no doubt about it," Fornell told the television station.
Firefighter Marcus Moore told WJBK the baby was full term and weighed about 7 pounds. He said he was glad his crew was able to save the child.
"You just want to do the right thing, so that you get the right results," Moore told the television station. "We were fortunate to do that today. It was surprising, the age that she was, I am pretty sure she was scared. But that's why we are here -- to take care of those situations."