Pearce made his senior debut in 2007 against Cavan. Hanley had previously won the Ron Barassi Medal for the best player of the International Rules Series for the Irish U-17 international rules team against Australia in 2005. It was there that he was first scouted by recruiters from Australia and he was targeted for recruitment by the Brisbane Lions as being a potential AFL player.
In 2007, Pearce was signed by the Brisbane Lions, and put on the rookie list with a view of converting him to Australian rules football. At the Lions, he was mentored by fellow Irishman Colm Begley who had previously played with the club for a season. Hanley made rapid progress and his adaptation to Australian football was almost as rapid as Begley's. He impressed in an early intra-club hit-out and was a solid performer for the Suncoast Lions.
Called up by coach Leigh Matthews, he made his debut in the final Lions home match in 2008 against the Carlton Football Club in front of a crowd of 35,000 at the Brisbane Cricket Ground, ironically replacing Begley in the side. At the end of the 2009 season, Hanley was elevated to the lions senior list.