Troy Kevin Taylor, 23, had denied murdering the 14-month-old boy during a two-week trial at the High Court in Christchurch.
He claimed that his then-partner and Ihaka's mother Mikala Stokes inflicted the boy's 59 fatal injuries on July 3, 2015 while he was out getting a tattoo.
But after four hours of deliberations, a jury of six women and six men were unanimous in finding Taylor guilty of murder.