Harriett was elected as the Member of Parliament for West Worcestershire in May 2010, where she has lived since 2006. She served as a member of the Work and Pensions Select Committee and from September 2012 to February 2014 she served as Parliamentary Private Secretary to the Minister for Employment in the Department of Work and Pensions. Harriett has represented the UK on the NATO Parliamentary Assembly, was elected Chair of the All-party Parliamentary Group for Russia and Vice-chair of the All-party Parliamentary Group for Occupational Pensions until she stood down in 2014.
Harriett was appointed to become the Prime Minister’s Trade Envoy to Russia before joining the Government in February 2014 as Assistant Government Whip. In the July 2014 reshuffle she was promoted to Lord Commissioner to HM Treasury. Following her re-election in 2015, Harriett became Economic Secretary to the Treasury (City Minister).
Prior to becoming an MP, Harriett enjoyed a successful, 20 year career in finance, specialising in currency markets for pension funds. She was on the National Council of Business for Sterling. She fought Stockton North for the Conservatives in 2005, gaining a 3.6% swing.
Harriett has always worked to encourage more women to get involved in politics and to work in financial services. She was a Changemaker for the charity "Working Families", which campaigns for more workplace flexibility.