Hanlon played for the well known Edinburgh youth football club Hutchison Vale, along with future Hibs teammate Danny Galbraith.

[5] Hanlon was an attacking midfielder who scored plenty of goals in youth football, but was converted to a defensive position after he signed for boyhood club Hibs.

[5] He played his first senior game for Hibs on 12 January 2008, against Inverness Caledonian Thistle in the Scottish Cup, due to injuries sustained by David Murphy and Lewis Stevenson.

[8] Hanlon went straight back into the Hibs team after returning from St Johnstone, but he was dropped soon afterwards by Mixu Paatelainen due to a defensive error he made in a match against Kilmarnock.

[11] Hughes again praised Hanlon before the start of the 2010–11 season, saying that he had a "real future" in the game and had the potential to play in the Premier League.

[28][29] Hibs announced in May 2024 that Hanlon and long-serving teammate Lewis Stevenson would be leaving the club at the end of the 2023–24 season.

[33] Hanlon was a regular in central defence during the 2011 UEFA European Under-21 Championship qualification campaign,[4] which ended in a play-off defeat by Iceland.

[34] Hanlon then captained an inexperienced side in November 2010 as head coach Billy Stark made initial preparations for the 2013 UEFA European Under-21 Championship qualification campaign.