Danny Martinez was sentenced to 18 years in prison for the December 2012 beating death of his cousin, 34-year-old Eddie Moreno.
Martinez could have received a sentence of five to 99 years or life in prison for killing 34-year-old Eddie Moreno.
However, the punishment range was reduced because the jury found the murder was committed as an act of sudden passion.
Prosecutors argued Martinez was high, drunk and angry when he kicked and beat his cousin repeatedly at an apartment their families shared.
Defense lawyers claimed Martinez was protecting family members after Moreno came home in a violent rage.
Deputy District Attorney Sunshine Stanek said it was a tough case for all involved.
"This is one family that's been completely torn apart," she said. "I hope that this verdict can give them some sort of closure. It's going to take a lot of time I'm sure, and now there's been two sons lost at least for a period of time and it's a very difficult situation which does call for a lot of high emotions."
Martinez could be eligible for parole after nine years.