Neil Graham Revill, 38, was convicted of first-degree murder in the fatal stabbing of Kimberly Crayton and second-degree in Arthur Davodian's death.
Davodian's body was found beheaded and stabbed 14 times.
Crayton, whose 14-month-old baby was spared, was stabbed 19 times.
Prosecutors said that Revill's DNA was linked to blood found on the child's dress.
He was sentenced without possibility of parole.