John was born in Dublin on 4th August 1959 and educated in St. Munchin's College Limerick, UCD and Freiburg University, Germany.
He contested his first general election in 1989. In 1991 he was elected to Dublin City Council and was Lord Mayor of Dublin from 1994 - 1995. In June 1997 he was elected to the Dáil. In June 2007 he was appointed as Minister for the Environment, Heritage and Local Government.
He is the author of the Green Guide for Ireland, Wolfhound Press 1990.
He has held many positions in The Green Party including Campaign Director for the successful anti-smog campaign in the 1980's. In 2002 he was elected as the party's first Cathaoirleach and was elected Party Leader in July 2007.
He had the distinction of being the first elected representative in Ireland to have an email address.
John is married to Penny Stuart. They have a daughter and a son and live in Ringsend in Dublin.