[3] Born in Lurgan, County Armagh, Sloan played for local side Glenavon as a youth, but signed for Manchester United in September 1937 aged 17 years old.

Throughout the war, Sloan remained a Tranmere Rovers player and between 1939 and 1946, he made 22 wartime league appearances and scored 15 goals for the club.

During the same season, he also played regularly for Bath City and his 18 goals helped them win the League West Cup in 1945.

During the subsequent 1946–47 season, he made 27 league appearances and scored one goal, establishing himself as a regular in the Arsenal team.

However, in the following season, 1947–48, Sloan lost his place to Archie Macaulay and he only made three league appearances as Arsenal went on to win the old First Division in 1947–48 without him.

[6][2][7] 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.

During subsequent seasons, he played for Torino, Udinese and Brescia, before returning to England and signing for Norwich City in December 1951.

Sloan was a Tranmere Rovers player when he played the first two games for the IFA XI, but had transferred to Arsenal by the time he made his last appearance.

In June 1946, when the FAI organised an Iberian tour, Sloan, together with Jackie Vernon, Billy McMillan and Jimmy McAlinden, was one of four Northern Irish players called up.

He also had spells as player/coach with both Lockheed Leamington and Bath City before emigrating to Australia as a coach in the Victorian Premier League, to link up at first with South Melbourne Hellas and then Brunswick Juventus.