He joined the company in 2016 becoming CEO the following year
The chief executive of Bus Éireann Ray Hernan is to leave his post in the coming months.
Company chairman Aidan Murphy said Mr Hernan is going to a senior role in another company.
He joined Bus Éireann in November 2016 as chief financial officer and became CEO in January 2017.
On his departure, Mr Murphy said: "He made a valued contribution by working closely with the board to take, and implement, the very difficult decisions required to stabilise the financial position of the company.
"Following a restructure of the business, he continued to work with all staff to ensure that all the recommendations included as part of a new Labour Court agreement, were fully implemented.
"This was a major achievement that has significantly helped to make the company more customer focused and competitive - a necessity in this challenging transport environment".
Stephen Kent, Bus Éireann's chief commercial officer, has been appointed acting CEO.
The firm recently announced the creation of 200 new jobs at 10 locations nationwide.
Bus Éireann also won the contract for Waterford services in a competitive bid, which will begin later this year.