Michael Jones, 46, must serve 25 years for killing his son Adrian. The boy's step-mother, Heather Jones, 31, has already been jailed for the same crime.
Officials say Adrian endured horrific torture in his last year of life, and was fed to pigs after his death.
A Kansas politician has introduced a law requiring people to report abuse.
Representative Louis Ruiz introduced Adrian's Act, which would require family members or residents of the household to report abuse to authorities.
Under current Kansas law, only "mandated reporters", such as healthcare workers, teachers, social workers, and law enforcement officers are obligated to report abuse.
"If you witness child abuse, I don't care if you're a mandated reporter or not, we should report these things," said Adrian's grandmother, Judy Conway, who praised the bill.
The little boy's remains were found in a barn on a property rented by the Jones family in November 2015.
He is believed to have died from starvation months earlier.
Investigators had gone to the home after receiving reports of domestic abuse.
While the couple was awaiting trial, their landlord discovered photos and videos on their computer meticulously documenting the horrific abuse Adrian had endured.
During sentencing, Detective Stuart Littlefield choked back tears as he described the final year of Adrian's life, which he said was the worst crime he had seen in his 23-year career.
"Imagine the screams of a 7-year old boy", Mr Littlefield said describing the abuse.
"And when his killers could no longer stand the stench of his body he was fed to pigs," he said.
A judge in Kansas has sentenced a man to life after he was convicted of murdering his seven-year-old son, torturing him and recording the abuse.