Troy Taylor has been found guilty of the murder of toddler Ihaka Stokes in the Christchurch High Court on Thursday.
It took the jury four hours to come to their decision.
Taylor looked stunned and muttered "f***ing bullsh*t" under his breath when the decision came.
There were gasps and crying from the public gallery as the verdict was read out.
Ihaka was 14 months old when he died after suffering 59 injures in the days leading up to his death on July 3, 2015.
Taylor pleaded not guilty to assaulting Ihaka on July 2, 2015 and not guilty to the toddler's murder, and throughout the trial continued to claim his innocence.
He also said during the trial he lied about hearing a bang coming from Ihaka's room the night the toddler died and said he did this to protect Ihaka's mother Mikala - the only other person in the house that night.
The defence argued it was her who inflicted the fatal blows and Taylor says he came home to find Ihaka struggling to breathe and thought Mikala was responsible.
"I lay in bed - I didn't know what to do," he said.
"I didn't want to get her into trouble, I really didn't know what to do."
Taylor has been remanded in custody until sentencing on June 9.