Tyler Sullivan, 30, was charged Thursday with criminal homicide and two counts of aggravated assault. He was sent to the Bucks County Correctional Facility and was denied bail.
According to officials, police officers were dispatched to the 1000 block of Radcliffe Street late Wednesday night for a baby in cardiac arrest.
Police administered CPR, but the baby was taken to Lower Bucks Hospital where he was pronounced dead a short time later.
A doctor who examined the baby said he suffered contusions, bruising and abrasions throughout his body, officials said.
According to investigators, Sullivan violently shook the baby at least two times on Wednesday and at least six other times in the past six weeks.