Gill Madden started her career working as a computer manager at the Medical Research Centre at Northwick Park Hospital in Harrow. In 1973 Gill moved into higher education progressing into a senior manager position at Middlesex University in North London. At Middlesex Gill was responsible for the provision of academic computing and audio visual support services to staff and students ( 23,000 ) both abroad and based on local campuses. Whilst at Middlesex Gill served on many committees and chaired several including the Universities Environmental Advisory Committee. Gill took early retirement from Middlesex University in August 2006.
In 1977 Gill was appointed as a lay magistrate and is now a magistrate in Barnet. Over the years Gill has been elected to serve on the Bench Training and Development Group and Fines Panel and in 2005 Gill was elected to be Bench Chairman for Barnet. Her duties as Bench Chairman include a pastoral role for over 100 magistrates, dealing with disciplinary matters and appeals and attending pan London meetings with the Judiciary and HMCS directors.