The Saints signed Charlie at the beginning of January 2017 following his release from Aldershot Town at the end of 2016. The striker scored 15 goals for The Shots during the 2015/2016 season after his arrival from Luton Town the previous summer. However, he found first team opportunities limited during the 2016/2017 campaign after recovering from an ankle injury picked-up during a pre-season game with MK Dons.
Walker was pursued by a number of other clubs but made no hesitation in signing an 18-month contract at Clarence Park.
Charlie left the Saints in the summer of 2018 and signed for Eastbourne Borough.