A Medical Council Fitness to Practise Committee has found Dr Omar Hassan guilty of professional misconduct and poor professional performance on multiple counts.
The verdict follows a ten-day inquiry held earlier this month.
The issue of any sanction will now be dealt with at a full meeting of the council within a few months.
It must also be approved by the High Court.
Dr Hassan will have an opportunity to address that meeting and make recommendations as to sanction.
It will also be open to the doctor to challenge the findings and any sanctions by the High Court.
Dr Hassan, who qualified in Sudan, was not present at the verdict this evening but listened to it by telephone.
Speaking by telephone after the verdict, he said he was not happy with the findings and will be seeking legal advice.
There were 11 allegations and sub-sets of allegations against him.
Dr Hassan totally rejected the allegations and claimed he had been the subject of unfair treatment and career damage.
The inquiry arose from complaints made concerning Dr Hassan's care of patients and his interactions with colleagues, at the Midland Regional Hospital Portlaoise, Mayo General and Galway University Hospital during various periods from 2012 to 2014.
Last year, the council secured a High Court order suspending Dr Hassan from practice, in the public interest, pending the outcome of this inquiry.
It has been one of the longest inquiries of its kind held by the council.