President Michael D Higgins and his wife Sabina led mourners in the funeral Mass, along with Barney's partner Tina, his brother Sean Og, sister Marie and nephews, nieces and extended family.
Famous faces mingled among the mourners including Phil Coulter, Declan O'Rourke, Damien Dempsey, Sinn Fein president Gerry Adams, Eamon Campbell, Donal Lunny, Paddy Reilly, Liam O Maonlai, Maire Breatnach, Anne Doyle and Dan McGrattan.
Phelim Drew, the son of the late Ronnie Drew, and classical guitarist Michael Howard said the readings during the Mass.
Taoiseach Enda Kenny was represented by his aide-de-camp Commandant Michael Tracey.
The congregation burst into spontaneous applause as a variety of reels and songs beloved by 'Banjo Barney' were performed by friends.
And as Barney's coffin was walked from St Patrick's Church in Trim, Co Meath, emotional fans marked the moment by clapping to the beat of the music.
The last of the founding members of the Dubliners was remembered by Fr Mark Mohan as leaving thousands of people with treasured memories.
"In these last few days, Barney's passing has changed the course of the McKenna family life," Fr Mohan said.
"It has changed also Dublin, Ireland, and indeed the music world at large. It has lost one of its greatest.
"The last man standing, so to speak, of the original Dubliners has been taken from us." Barney (72) died unexpectedly last Thursday.
He was the last of the founding members of the renowned Dubliners, formed in 1962 in the now famous O'Donoghue's pub in Dublin.
The other original members, Luke Kelly, Ciaran Bourke and Ronnie Drew died in 1984, 1988 and 2008.