At the 1997 general election, O'Meara was an unsuccessful candidate in the Tipperary North constituency. At the 1999 local elections, she was elected to Nenagh Town Council. She was a candidate again for Dáil Éireann at the 2002 general election, increasing her share of the vote from 10.3% to 13.5%, but again failing to be elected.
During her second term in the Seanad (2002–07) O'Meara came to national prominence as a health campaigner. She drove the Nenagh Hospital Action Group, one of many groups formed to oppose Government health policy, contained in the Hanly report, to remove emergency services from smaller general hospitals. She was the Labour Party's front-bench spokesperson on Childcare from 2003–07. She was the whip of the Labour group in Seanad Éireann. She was an unsuccessful candidate at the 2007 general election for Tipperary North, getting 10.3% of the vote. She did not contest the Seanad elections in 2007.
Following the 2007 election, O'Meara set up Alchemy Communications, a consultancy, with two other experienced public relations and communications consultants. Since September 2008, she is head of Advocacy and Communications for the Irish Cancer Society.
In 2011, O'Meara unsuccessfully contested the Labour Party presidential nominee election. The nomination going instead to party president and former TD, Michael D. Higgins.