The 35-year-old was found dead in a property in Caledon Court in East Wall this afternoon.
He founded Inner City Helping Homeless and became a councillor in 2019.
His body has been taken to the mortuary in Whitehall, where a post mortem examination is due to take place.
Deputy Lord Mayor of Dublin, Joe Costello, has been paying tribute to his fellow councillor:
"We're absolutely shocked at the thought that somebody as young and so active and energetic and had done so much work for the local community, and had been a founding member of Inner City Helping Homeless, should go suddenly. He's a colleague of mine, and we had worked together in the north inner city on a lot of issues."