Graydon Scott Boyd, named for his great-great-grandfather, was born at 10:18 p.m. on Thursday, weighing in at 6 lbs 4 oz. He's Boyd's second child with his wife, Taylor Boyd.
The singer has an elder son from a previous relationship.
The new parents were overjoyed with their Christmas gift to themselves. "The last week of December will forever be a huge week in the Boyd family," Boyd told reporters from PEOPLE.
Boyd himself turns 39 years old on Sunday.
Craig and Taylor married in April 2016, just four months after their daughter, Dakota Lynne was born. The couple has organized a series of gag family photos to announce their pregnancy and keep fans updated.