The man called emergency services at about 5am local time on Thursday in Collier County and said the reptile had bit his leg. The alligator was about two metres long.
He was bleeding profusely and the man's skin had been ripped off, local media reported, citing emergency call records. The man said he wrapped his shirt around his leg to try to contain the bleeding.
Media reports suggested the animal in question was a mother that was protecting its hatchlings.
When police arrived on scene, one tended to the man while the second located the alligator and alerted a trapper.
The trapper secured the alligator and removed it from the community.
Alligators tend to prefer freshwater lakes, slow-moving rivers and wetlands, according to the Florida Fish and Wildlife Conservation Commission. The animals reside from south-east Oklahoma through North Carolina and Florida.
Alligators are most active when temperatures are between 28°C to 33°C.