West was born on 14 September 1966 and was raised in Sydney, Australia. She was educated at Ravenswood School for Girls. She studied at the University of Sydney and gained a master's degree in Chinese politics from the School of Oriental and African Studies, University of London.
West is fluent in five languages, including Mandarin Chinese, which she became proficient in during her time living in Nanjing.
From 2 May 2002 to 22 May 2014, West was a member of the Islington London Borough Council representing the Tollington Ward. She was leader of the council's Labour Party group from 2004 to 10 October 2013 and Council Leader from 6 May 2010 to 10 October 2013.
She was elected Member of Parliament (MP) for Hornsey and Wood Green in the 2015 general election.
Following the election of Jeremy Corbyn as Leader of the Labour Party, Catherine was promoted to the Official Opposition Frontbench as a Shadow Foreign Office Minister.
During the 2016 EU membership referendum Campaign, West was involved with Britain Stronger In Europe, campaigning for the UK to remain within the European Union, arguing that "Britain would be stronger, more prosperous, more secure and more peaceful" if they were to remain within the EU. West's constituency of Hornsey and Wood Green secured the highest remain vote in the UK with 81.5% voting to remain. Following the EU referendum, West confirmed she would vote against invoking Article 50 should a vote come before parliament.
In September 2016, she founded the All-Party Parliamentary Group on UK-EU Relations, that seeks to secure a positive and progressive relationship between Britain and the EU. This group has cross-party support with Green Party Leader Caroline Lucas, former Conservative Secretary of State for Education Nicky Morgan and Former Labour Higher Education Minister David Lammy among its elected officers.
In January 2017, West voted against triggering Article 50 of the Lisbon Treaty, the process by which EU Member States may use to withdraw from the European Union, along with 46 other Labour Party Members of Parliament.
West opposes the renewal of Trident nuclear weapon system. In September 2015, West along with Tulip Siddiq and Keir Starmer wrote a letter to British prime minister David Cameron seeking urgent action to address the refugee crisis due to the Syrian Civil War.
West was sacked from the Labour frontbench in June 2017 after she voted in favour of an amendment to the Queen's Speech which called on the UK to remain in the European Single Market, in defiance of the Labour whip.
West is a Quaker. She is one of three Quakers elected during the 2015 general election, the others being Ruth Cadbury and Tania Mathias.