Brennan is a recipient of the Irish Chair of Poetry Fellowship and writes both poetry and prose. 

His video-poem Four Attempts at Making a Human won an award at the Drumshanbo Written Word Weekend, Leitrim, in 2022

Brennan has read at literary festivals in Colombia, Nicaragua, Mexico, Italy, Ireland and the US, and his work has been translated into Spanish, Italian, Galician and Greek

He divides his time between Mexico and Ireland, and his most recent book, Let the Dead (2023), is available from Banshee Press.