"The reason I was fired is just ridiculous," Lopez told CNN late Wednesday night. "It is a ridiculous rule, really. What was I supposed to do? Just let the guy drown?"
The incident occurred Monday at Hallandale Beach in southern Florida.
Orlando-based Jeff Ellis and Associates, the company Lopez worked for, said lifeguards cannot go beyond the perimeter of the beach they are responsible for overseeing.
But that day, a beachgoer rushed to Lopez's lifeguard station to alert him to a man who was drowning.
The man was some 1,500 feet outside the company's protection zone in an area where signs warn visitors to swim at their own risk.
Even though he knew it was outside the company protection zone, Lopez ran into the ocean toward the struggling man and pulled him ashore.
The man, he said, had turned blue.
"He was having a lot of trouble breathing," Lopez said.
A nurse at the beach tended to the victim until emergency medics arrived and rushed him off to a hospital.