Le Couteur grew up in the Canberra suburb of Yarralumla. Her father was the British physicist Kenneth Le Couteur. She was educated at Telopea Park High School and the Australian National University where she studied economics. She moved to Nimbin after the holding of the Aquarius Festival there in 1973 and stayed there for 11 years. While in Nimbin she was instrumental in forming a pre-school and primary school and became a solar (photovoltaic) panel retailer and installer. ^[2] She subsequently moved back to Canberra and worked for the federal and territorial governments firstly in information technology and later in renewable energy policy.^[3] She later became an Executive Director of locally based, now ASX listed, company Australian Ethical Investment as well as their information technology manager.^[4]

Le Couteur was active in the local environment community. She was at the time of her election one of the two national councillors of the Australian Conservation Foundation (ACF)^[5] and had previously been on the ACF's board. She was a keen supporter of groups such as the Australian and New Zealand Solar Energy Society, Pedal Power, Oxfam, Anglicare and the Conservation Council.^{[citation needed]}

Le Couteur has dual British-Australian citizenship.^[6]

Le Couteur stood for the ACT Greens in the electorate of Molonglo in 1998 supporting the Green incumbent Kerrie Tucker. She remained active in the Greens and stood again in Molonglo in 2008. Before the 2008 election the Greens had one member, Deb Foskey. Prior to the 2008 election polling conducted by Patterson Market Research and published in The Canberra Times suggested the Green vote had significantly increased since the last election at the expense of Labor, with the Liberal vote remaining relatively unchanged. Commentators predicted the Greens would hold the balance of power and decide who forms government. The Greens stated they were willing to court both major parties.^{[7][8][9][10]} At the close of counting on election night, with 82.1 per cent of the vote counted, Labor had obtained 37.6 per cent of the vote across the ACT, with the Liberals at 31.1 per cent and the Greens at 15.8 per cent. Swings were recorded against both the Labor (−9.3 per cent) and Liberal (−3.7 per cent) parties with a +6.6 per cent swing towards the Greens. This resulted in the election of Amanda Bresnan, Meredith Hunter, Shane Rattenbury and Caroline Le Couteur. Le Couteur, Bresnan and Hunter were defeated at the 2012 election.

Le Couteur stood as a candidate for the new Murrumbidgee electorate in the 2016 election, and was successfully re-elected.^[11] After being sworn in as a member of the Assembly, Le Couteur was appointed chair of the Parliamentary Planning Committee.^[12] During her time in the Assembly, Le Couteur was involved in the passage of legislation committing the ACT to a 'zero emissions by 2050' target and a ban on political donations by the property industry. She announced her retirement from politics ahead of the 2020 election.^[13]

Le Couteur has described herself as an "ageing hippie" and has admitted to smoking cannabis in her youth, as well as having tried acid.^[14]

• Caroline Le Couteur: Website
• Caroline Le Couteur: Legislative Assembly Members' page
• Caroline Le Couteur's Inaugural Speech
• Caroline Le Couteur on Facebook