Born in Camberwell, south London, List made his professional debut in the Gills’ 3-1 victory against Swindon Town on Boxing Day 2015. He came through the Crystal Palace academy, but was released by the Eagles during the 2014/15 season.
After playing a number of development games for the Gills, he signed a one-year professional deal in May 2015. List made six appearances, all from the substitutes’ bench, for the club during the 2015/16 season. He signed a one-year contract extension in June 2016.