 With the "Rossoneri" he progressed through each youth category, from "Esordienti" to "Primavera".In March 2015, Locatelli signed his first professional contract with Milan, effective from 1 July 2015 until 30 June 2018.Locatelli received his first ever call-up to Milan's senior team ahead of the away game against Udinese played on 22 September 2015; he, however, remained an unused substitute.