The Medical Council's Fitness to Practise Committee has found Professor Martin Corbally guilty of poor professional performance on three counts.
Prof Corbally was before the inquiry in relation to the wrong mouth operation carried out on a two-and-a-half-year-old girl at Our Lady's Children's Hospital, Crumlin, in April 2010.
A decision on any sanction will be made by the full Medical Council at a later stage.
*** UPDATE: This decision was overturned by the Supreme Court in 2015 ***
Committee chairman Prof Gerry Bury said the inquiry had heard significant evidence of systems failures and errors in surgical procedures at Crumlin.
Prof Bury said the hospital had an inadequate surgical booking and coding system.
He said a correct site of surgery policy was not implemented and there was an issue with clinical leadership.
Prof Bury said the system of "surgical pause" where issues arise before an operation did not come into effect in this case.
He also said it was still unclear if a comprehensive surgical booking system was now in place.
Prof Corbally later expressed disappointment with the inquiry verdict.
He said he had always endeavoured to do the best for his patients.
Prof Corbally also said he was happen that the patient had made a full recovery.
Following the verdict the defence team for Prof Corbally asked that any sanction against him be proportionate.
Senior counsel Eileen Barrington said the council should consider the lowest level of any sanctions.
These sanctions would be advice, admonishment or censure.
Ms Barrington said this was especially relevant following the committee chairman's remarks about systems concerns at Crumlin hospital.
Meanwhile, Our Lady's Children's Hospital, Crumlin has apologised for the distress and upset caused to the patient and family affected.
In a statement, the hospital said it implemented improvements in its practices following the incident.
The hospital said it also wanted to reassure the public that it operates a Correct Site Surgery Policy.
Our Lady's Hospital Crumlin said it was not invited to participate in any part of the Medical Council hearing and so it did not have an opportunity to respond directly to any concerns raised.
