Born in Carrickfergus, Beattie became involved in politics by assisting the Democratic Unionist Party (DUP) during elections. She became a party member in the early 1990s, and first stood for election to Carrickfergus Borough Council at the 1993 Northern Ireland local elections.
Although unsuccessful, she was elected for the DUP in East Antrim at the Northern Ireland Forum election in 1996, and sat on the forum's health committee. She gained a seat on Carrickfergus council in 1997, and held this in 2001, 2005 and 2011. She served as Mayor of Carrickfergus in 2003–4 and sits on a large number of committees. She is currently serving as an alderman.
Beattie has also served as secretary for the DUP's East Antrim branch and for the East Antrim Imperial Association, and was previously a member of the Association of Loyal Orangewomen of Ireland.
|Northern Ireland Forum|
|New forum|| Member for East Antrim
| Mayor of Carrickfergus