Dr Tony Holohan said the loss of his wife left him with the "desire to do something meaningful in her memory" as he steps down as CMO.
The top doctor was the face of the Covid response in Ireland over the last three years as he fronted press conferences and became the bearer of bad news.
Dr Holohan's wife Emer died in February of 2021 and has been cited by him as one of the reasons for his departure.
