Delighted at gaining the position, Eibhlin sprang straight into mayor mode and vowed to raise awareness of issues in relation to the homeless in the capital.
But first her family will have to get used to living in the city centre, a move that will mean husband Ken will have a longer commute to work in Artane every day.
But for the couple's three daughters the Mansion House will make the perfect address.
"Lisa is studying in Trinity so she will be just around the corner, and Aisling is in Alexander College so the Luas will be handy," said Eibhlin.
"Our other daughter Clare is studying medicine in Aberdeen, so things won't change too much for her," she added.
Eibhlin doesn't know when the Mansion House last had a dog in residence, but says Sam will be the perfect guard for the historic property.
"I'm really looking forward to taking on the role, and hope that I can raise awareness on several issues including the homeless, not just in putting up a roof for them but in areas like treatment of mental health issues and drink and drugs," Eibhlin told the Herald.
"I hope to bring together the world of business together with voluntary bodies to achieve some aims, as well as encouraging young people to get involved in politics," she added.
Eibhlin is a former secondary school teacher and a member of Dublin City Council since 2003.
But when her daughters are asked if they have any interest in following in their mother's footsteps they admit "No".
Ms Byrne is the sixth woman to occupy the position and the first female Fianna Fail Lord Mayor since 1939. Labour councillor, Emer Costello was last night elected deputy mayor -- the first time both jobs have been occupied by women.
She received 29 votes following a pact with the Labour party members of Dublin City Council. She defeated Fine Gael's Mary O'Shea and Sinn Féin's Criona Ni Dhalaigh.
She is to be the 339th Lord Mayor of Dublin and the last Fianna Fail councillor to take the job before the mayoralty becomes a directly elected post in 2011.