The sentence came after the judge first overruled a motion for a new trial.
Tony King was convicted of first degree murder, arson and child abuse by a Buchanan County jury in May.
Friday, King was also sentenced to two, 15-year sentences for the arson and child abuse convictions.
King killed his 7-year-old son then set fire to their Harrison County home in 2012.
King's attorney requested the change of venue to Buchanan County in March of 2012.
King has also been charged with killing his cellmate in the Buchanan County Jail in June.