Hiller began his youth career in 2003 at FC Grün-Weiß Gröbenzell, before moving to 1860 Munich's youth academy in 2008. He made his debut for the reserve side on 23 April 2018 against FV Illertissen in the Regionalliga Bayern, with the match a finishing as a 1–3 away loss.[2] For the 2017–18 season, Hiller joined 1860's first team, which had been relegated to the Regionalliga. He made his debut on 13 July 2017 in a 4–1 home win against FC Memmingen.[3] 1860 Munich finished as champions of the Regionalliga Bayern,[4] and subsequently won the promotion play-offs to the 3. Liga against 1. FC Saarbrücken.