Adam Carrol Palmer, 29, who served time in prison for beating another child in 2003, pleaded guilty to causing injuries to the then-2-year-old child, who now lives in a nursing home for children in East Texas.
The child's mother, Ryka Telan Hopper, 29, was convicted by a Tarrant County jury in November and sentenced to 40 years in prison for failing to protect the child from Palmer's repeated beatings.
"He is a cruel coward," prosecutor Eric Nickols, who tried the case with Kelly Meador, said in a written statement. "He preyed on the weakest and most innocent among us. He deserves every second he got."
Hopper's defense attorneys had described Palmer as a "despicable, diabolical man" who preyed on the uneducated Hopper. But Hopper took the stand in her own defense and told a rambling, inconsistent tale that included repeated admissions that she was a liar.
Palmer was sentenced in the state District Judge Louis Sturns' court.