After originally studying in the sciences and dabbling in the theatre, Tierney received a B.A. in English from the University of Toronto and an M.A. in Creative Writing from the University of New Brunswick. Since then, Tierney has published poems in several literary journals throughout Canada and Ireland.
Tierney was awarded the 2006 K.M. Hunter Artist Award for literature. Tierney also won both 1st place and 2nd place in This Magazine's 2005 Great Literary Hunt and 1st place in Maisonneuve magazine's 2006 literary competition.
Tierney is the author of the full collections The Hayflick Limit and Full Speed Through the Morning Dark, the chapbook Trans-Mongolian Express, and the thesis novella Merely Players.
The Hayflick Limit was nominated for the 2010 Ontario Trillium English Language Book Award for Poetry.
Tierney won the 2013 Ontario Trillium English Language Book Award for Poetry for his third full collection, Probably Inevitable.
Tierney lives in Toronto with his wife, Charmaine Lau Tierney.
- Full Speed Through the Morning Dark Toronto: Wolsak & Wynn, 2004. ISBN 0-919897-97-5
- The Hayflick Limit Toronto: Coach House, 2009. ISBN 978-1-55245-217-2.
- Probably Inevitable Toronto: Coach House, 2012. ISBN 9781552452615.