After only a brief spell with Sheffield United, Sloan joined Milan for the 1948–49 season, and as a result he became the first Irish footballer to play in Serie A. Playing in a team that also included Gunnar Nordahl and Albert Gudmundsson, Sloan went on to score nine goals during the season. The first of these came on 24 October 1948, when he scored the third goal in 3–1 home win against Triestina. On 5 June 1949, in the final game of season, he scored twice in a 3–2 win against Sampdoria. His goals helped Milan finish the season in third place behind Torino and Internazionale. During subsequent seasons, he played for Torino, Udinese and Brescia, before returning to England and signing for Norwich City in December 1951.