Dr Tony Holohan has returned to work as he resumed his duties as Chief Medical Officer.
A Department of Health spokesman confirmed that he had returned to his post on Monday.
The top doctor had temporarily stepped down after the tragic passing of his wife Emer earlier this year.
Dr Emer Holohan (nee Feely), who had been living with a terminal form of blood cancer since 2012, died in February.
Dr Holohan has been the public face of the State's response to the unprecedented public health emergency.
He had also previously taken time off work last summer after Emer entered palliative care in early July.
Dr Feely was a specialist in public health medicine and a medical graduate of UCD.
And she tragically passed away at Our Lady's Hospice, Harold's Cross, Dublin on February 19.
Paying tribute to his wife at her funeral mass at St Pius X Church in Dublin., Dr Holohan said she was someone who lived for her family.
With his two children by his side, Dr Holohan described Dr Feely as a "loving, caring, warm, witty and sunny person".
"Emer, this is the day that was always coming, we knew that, we all did," he added.
"After that dreadful day in September 2012, you and I both knew you would leave us before your time, and you have.
"Your suffering is over, the pain, the anguish and the tears are at an end.
"We gather in this cruelly constrained way to mark your passing, in word, prayer and in song.
"This is not going to be a chronology of your life, I think too much of you to try summarise you in a few short minutes of words for people who may not know you.
"For those who do know you, they don't need me to set it out."
He praised his wife in how she handled her long illness.
"Once upon a time, I worried about how you would ever cope with the adversity we met along the way of our lives.
"I thought your soft and sensitive nature might mean you would find some of life's tests too much for you.
"How little I know," Dr Holohan added.
"You faced the illness without fear or anger.
"Sure, you asked the usual questions about why us and why me, but you didn't dwell on them.
"You didn't let it rule you or define you, no matter how it impacted you.
"Amazingly, it was in how on the countless occasions we received the proverbial bad news, you would get up the next day and simply choose to put it to one side, to get on with things and to be there for Clodagh and Ronan.
"For it was Clodagh and Ronan that kept you going, and in them and the people they are, all that they have and will achieve in their lives, that your greatest legacy will be felt."
