The GMC said the ruling was clear Dr Squier "had acted irresponsibly".
Dr Squier said the tribunal's conclusions "felt absolutely terrible".
The paediatric neuropathologist, who had acted as an expert witness in six court cases including the deaths of four babies and a 19-month-old child, was also suspended from her post at Oxford's John Radcliffe Hospital.
She said: "It was extraordinarily tough, very difficult, probably the worst sort of abuse I've been through in my life.
"I was at my lowest when I came back to Oxford from the Manchester hearing with all of those words ringing in my ears."
Dr Squier disputed the existence of brain trauma caused by violently shaking an infant and has argued that she was scapegoated for challenging the mainstream view.