He previously played for the Rochester Lancers in the MISL (winter league) and San Antonio Scorpions of the North American Soccer League (spring/fall). College and amateur
During his college years Hannigan also played with the Ocean City Barons in the USL Premier Development League. Hannigan was 7-0-3 as a starter earning five shutouts and remains the club"s single-season record holder for goals against average (056) and saves (75).
Hannigan was drafted by the MetroStars with sixth pick of the third round of the 2005 Master of Library Science Supplemental Draft, but was not offered a contract by the team, and instead signed with Irish side Bray Wanderers of the League of Ireland.
He returned to the United States in 2006 to play for the Rochester Raging Rhinos in 2006, but never saw any first-team action, and moved on to Miami Football Club in 2007. He was Miami"s first-choice goalkeeper throughout the 2007, playing 22 games for the team
After a year playing indoor soccer with the New Jersey Ironmen in 2008, Hannigan returned to Miami in April, 2009, and played 23 games for the team in the USL First Division before being released at the end of the season. After a year out of the game in 2010, Hannigan signed to play with the Ocean City Nor"easters in the USL Premier Development League in 2011.
On November 19, 2011 the Rochester Lancers announced they have signed Hannigan to their squad.
He was released for disciplinary reasons in January 2014. Hannigan signed in January 2012 with expansion side San Antonio Scorpions of the North American Soccer League. Hannigan began the 2013 NASL season as the number one keeper for San Antonio Scorpions.
He was not re-signed for the 2014 season.