Peadar Kearney was born in Dublin in 1883. After leaving school he worked at various labouring jobs and was for a while a stagehand at the Abbey Theatre. He joined the Gaelic League and theIrish Volunteers and fought in 1916. He took part in the Civil War on the anti-Republican side, but afterwards became disillusioned and took no further part in public affairs, working as a labourer for the rest of his life. He is thought to have died in Dublin in 1942.

Peader Kearney wrote a great deal of poetry: patriotic verse, comic verse, love songs and parodies. Today he is best remembered for having written the original, English-language, version of Amhrain na bhFiann and because he was an uncle of Brendan Behan.