A SWAT team used concussion grenades to distract the gunman, who was killed in an exchange of gunfire, The Atlanta Journal-Constitution reported.
The freed firefighters sustained minor injuries and were treated at a local hospital, the newspaper said.
The Gwinnett County firefighters had responded to the location, northeast of Atlanta, in response to a call for medical assistance, police said. WSB-TV, Atlanta, reported the gunman falsely reported a heart attack.
The TV station said the incident took place at a house that had been foreclosed upon. Gwinnett police Cpl. Ed Ritter said the man demanded his cable TV and utilities be restored, the AJC said.
"It's a very bold act," Gwinnett fire Capt. Thomas Rutledge said. "People can often be desperate. We don't know what the situation could be."
The newspaper said the man, whose identity had not been reported, initially held five firefighters but released one to move a fire truck.