According to the Springdale Police Department, 23-year-old Tremelle Deshun Overton was arrested after authorities found his stepson unresponsive and not breathing Wednesday night.
Police reportedly interviewed Overton and the child's mother before the arrest was made.
Overton was booked into the Washington County Detention Center on Thursday, and is facing first-degree murder.
His bond has been set at $100,000.
According to police, the infant was sent to the state crime laboratory, and the investigation is ongoing.