She studied at Birmingham University and worked in community education before entering politics.
From 1997 until 1999, she served as personal assistant to Helen Liddell MP.
Gillon was elected in the 1999 Scottish Parliament election, taking 16,755 votes (43.02%).
She was re-elected in 2003 with 14,800 votes (46.62%) and in 2007 with 13,835 votes (41.5%).
She served as Labour's spokesperson on rural development until her defeat in 2011.
She was co-chairperson of the Cross Party Group on Malawi and worked with civic society across Scotland and in the Clydesdale constituency, to develop better links between the two countries.
She was defeated in the 2011 Scottish Parliament election by SNP candidate Aileen Campbell by 4,216 votes (14.1%).