Newton began her career as a marketing officer for businesses including Citibank and American Express. During her six years working for American Express, Newton was responsible for strategic planning, marketing and promotion of the card in the United Kingdom. In the early 1990s, Newton served as the director of Age Concern England.[4] After leaving this post, Newton served as a founder and the initial director of The International Longevity Centre.[5]
Newton was first elected to the House of Commons in the 2010 general election. She beat the Liberal Democrat candidate by 435 votes. In 2015 she won re-election with 44% of the overall vote.[7] After both elections, Newton was one of four MPs sworn into office after taking their oaths in Cornish.[8][9]