glennon first held political office when he was elected to seanad éireann in a by-election. he remained there until 2002 when he was elected to dáil éireann at the 2002 general election. glennon was vice-chairman of the oireachtas committee on arts, sport, tourism, community, rural and gaeltacht affairs from 2002 to 2007. he was also a member of the oireachtas transport committee and of the oireachtas committee on procedures and privileges. glennon chaired a session of the dublin forum – a fianna fáil project to allow dublin residents discuss issues of political significance. he was part of the tv3 rugby world cup coverage in 2007.