He was a member of the Transport and Tourism Committee, as well as the Fisheries Committee. Ó Neachtain was instrumental to the recognition of the Irish language as an official working language of the European Union.
After obtaining a BA (hons) in 1969, Ó Neachtain became a school teacher. He worked in this capacity through the 1970s and 1980s. He was involved in regional politics around Galway and western Ireland from 1979, and served as a member of Galway County Council from 1991 to 2002. He made his first foray into European politics when he was appointed as a member of the Committee of the Regions in 1994. He was an unsuccessful candidate for the Galway West constituency at the 1997 general election.