McIntosh was elected to the House of Commons in the 1997 general election for the Vale of York which she won by a comfortable 9,721 majority and held the seat without difficulty until it was abolished in 2010. She was promoted to the Opposition frontbench in 2001 as Spokesperson for Culture, Media and Sport and has since held a number of front bench positions including Transport (2003–2005), Foreign Affairs (2005), Work and Pensions (2005–2007), and Environment, Food and Rural Affairs (2007–2010), though never at Shadow Cabinet level. McIntosh was elected as Chairman of the Environment, Food and Rural Affairs Select Committee in 2010. In 2014 she received wide acclaim for her "robust chairmanship" and "tackling the establishment head on".