Thomas Haining, who was 19 at the time of his daughter Mikayla’s death, inflicted “catastrophic and unsurvivable” brain injuries on her, the High Court in Edinburgh heard.
The newborn, who was left in a coma with a fractured skull and several broken ribs, died in her mother’s arms the following day after doctors decided Mikayla’s head injuries meant “survival was unlikely”.
She had suffered a heart attack caused by the head trauma.
Haining, now 21, had originally been charged with murdering the baby, but had always denied it.
Prosecutors concluded a trial on the greater charge was not “in the public interest” and last week accepted his guilty plea to the lesser charge of culpable homicide.
Questioned at length on the decision by the judge, Lord Pentland, prosecutors said admitting the lesser charge would be acceptable “in the context provided for the injuries”.
Haining, they added, had acted with “wicked recklessness”, suffering from “a loss of control” which had “catastrophic consequences.”
The court heard that, while his ex-girlfriend Shannon Davies slept upstairs at their home in Inverness, Haining claimed to have taken Mikayla out of her Moses basket to feed her in the early hours of 8 June 2017.
He said she then became sleepy and unresponsive, but phone records show he searched online for information on babies in a coma during this time.
One of the searches was: “What happens if a newborn baby is shake (sic) hard?”
Ms Davies described Haining as “being in a panic”.
Paramedics could not resuscitate the infant, who was taken to hospital and placed in intensive care with a ventilator.
A man in the public gallery shouted: “You murdering f*****g bastard, conning everyone”, as Haining, wearing a black suit and tie with black trainers, was led away.
Detective Inspector Brian Geddes said: “Haining took the life of his daughter, a beautiful baby girl, in the most horrendous of circumstances.
“At just days old, Mikayla should have been safest in the arms of her father – instead he inflicted injuries so severe that she would never recover.”