Joanne Marie Platt was elected Member of Parliament for Leigh at the 2017 General Election, succeeding Andy Burnham, who left Parliament to become the Mayor of Greater Manchester. She is Leigh's first female MP.
On July 13, 2017, she became Parliamentary Private Secretary to Angela Rayner and she is also a Member of the Communities and Local Government Select Committee. Platt was a councillor and was Portfolio holder for Children and Young People's Services on Wigan Council, until she became a Member of Parliament. She officially stepped down as borough councillor on September 5, 2017. She won her Leigh seat with 26,347 votes or 56.2% of the total votes cast.