The St. Landry Parish Sheriff's Department charges Robert Henry Miller, III, 34, of 567 US Hwy. 190, with the second-degree murder of Victoria Renee LeJeune.
Deputies responding Feb.24 to what was reported as a medical emergency noticed bruising to the face and head of the infant.
Department records indicate an autopsy confirmed swelling of the toddler's brain due to multiple head injuries.
Miller, officials said, was the boyfriend of the victim's mother, Kimberly LeJeune, and had been previously charged with domestic battery against her.
He also has previous instances in which domestic abuse was alleged, officials said.