He retains the seat previously held by Catherine Murphy
Aidan Farrelly is the second TD to be elected in Kildare North.
The Prosperous based politician benefited greatly from the transfers of Labour's Angela Feeney and made it across the line, with 11,118 votes.
Farrelly was elected to Kildare County Council in 2019 and was re-elected again in June to serve a second term on the Clane-Maynooth MD.
The result means that the Social Democrats retain the seat previously held by retiring TD and party founder Catherine Murphy.