Seanan played underage football with Dungannon Swifts before joining the youth setup at English side Preston North End in 2009. He made his debut against Crewe Alexandra in the League Cup on 9 August 2011 and made 4 appearances for the club. He also had a loan spell at Burton Albion at the end of the 2011/12 season where he made 2 league appearances. Seanan was released on his return to Preston and later that summer he joined League Two side Bristol Rovers..

He spent two seasons at Bristol Rovers during which time he made 39 league and cup appearances but his time there ended with relegation from the Football League at the end of 2013/14. Seanan returned to Northern Ireland in August 2014 when he signed for Linfield. He made his debut for the Belfast club against Institute on 23 August 2014 and made 12 league appearances there before being released on 10 January 2015. Six weeks later he signed for Derry City ahead of their 2015 Premier Division season.

Seanan made twelve appearances in the Premier Division for Derry, scoring one goal in a 1-1 draw with Sligo Rovers. However, he left the club in July 2015 to move to America.