 Field began his career with spells in the youth systems at non-league clubs Kingstonian and Leatherhead and then joined the academy at Brentford at age 15.He was a part of the Bees' U15 team which won the Junior category in the 2012 Milk Cup.Field progressed to sign scholarship forms at the end of the 2012–13 season and made 45 appearances and scored two goals for the youth team over the following two seasons.