William Wakefield has been sentenced to life in prison for the murder of his 5-month-old stepson Lincoln.
He will serve a minimum non-parole period of 14 years and 9 months.
He has also been sentenced to 3 years concurrent for wounding with intent.
At the sentencing in Wellington's High Court on Friday, Wakefield cast his eyes downwards as victim impact statements were read.
The Upper Hutt man shook Lincoln to death in 2018 because he resented that the boy was not his.
Initially, Wakefield denied having hurt the baby but later admitted to police he shook the child because he was "gutted" the boy wasn't his and wanted to hurt him.
During his trial he pled guilty to manslaughter and wounding with reckless disregard for safety.
He was found guilty of murder in June 2019.