He followed Darlington teammate Matt Cornock to Second Division club Barnsley in May 1911. He performed well in pre-season and for the reserve team in the Midland League, and when first-team centre-half Tommy Boyle was sold to Burnley, Hanlon took his place. Although not of Boyle's quality, he was initially viewed as an adequate replacement, and kept his place for six matches, in the last of which, away to Leeds City, he scored what proved to be his only Football League goal. After Hanlon was injured, the reserve-team right half, Phil Bratley, came into the side and made the centre-half position his own for the rest of the season. Hanlon was a regular member of the 13-man training squad that prepared for FA Cup matches as Barnsley went on to win the competition, but did not make the team. He did make a further six appearances in league competition, generally standing in for Bratley when the latter was rested before or after a Cup tie.