Before help arrived, a neighbor, James R. Jenkins, 30, jumped into the water in an attempt to save Walker.
Jenkins was able to reach the child, according to police. Other bystanders, police officers, and Columbus Division of Fire personnel made several attempts to rescue the pair.
Jenkins and the child went under the water before they were able to reach the shore.
Rescue divers were able to pull both Jenkins and Walker from the water.
Jenkins was transported to Grant Medical Center, where he later died.
Neighbors were saddened to learn of Walker's death. Word spread quickly through the apartment complex where he lived.
"I just think they need to do something so nothing like this happens further. I feel for the family, feel for the little boy and feel for the man that died also trying to save him. I just hope nothing like this happens ever again," said neighbor Cedric Brown.
Brown has two daughters of his own, ages 3 and 4. He says while he is always careful near the water with his children he would like to see a fence put up on the perimeter of the lake.
According to fire officials, the boy was in the water for more than an hour.