Simon Harris, 37, on Tuesday became Ireland's youngest-ever prime minister to succeed Leo Varadkar, who unexpectedly resigned last month.
Irish parliament's lower house voted to approve Harris, a former higher education minister as their next taoiseach, or prime minister, by 88 votes to 69.
Addressing lawmakers after being elected the new prime minister, Harris said: "Today I accept this new role in a spirit of humility, ready for the challenge, and full of energy and determination about what can be achieved."
"I will be a Taoiseach who will listen. My message is simple. I will work every day to improve the lives of all in this country," he added.
After Varadkar's resignation last month, Harris became the new leader of the Fine Gael party.
