Career
McGuinness played at youth level for Tolka Rovers, Sheriff Y.C. and Bohemians before graduating to the Bohs first team, making his league debut as a substitute against University College Dublin in August 2002. He made his Irish Under 21 debut four days later in an international against Finland. Jason started the season well but was fined two weeks" wages and suspended for five games in May 2009 after racially abusing Benin captain Romuald Boco during a game between Sligo Rovers and Bohemians on 5 May 2009.
On his return, he struggled to find form and lost his place to Ken Oman.
Despite putting in a superb performance in the Setanta Sports Cup Final, Jason and Bohemians had a disappointing 2010 season where the club lost their league title on goal difference and failed to make an impact in Europe where they made an embarrassing exit to Welsh side The New Saints. When McGuinness" contract expired at the end of the 2010 season, Bohemians were unable to offer new contracts due to financial troubles and Jason was released from the club
On 25 January McGuinness signed a one-year contract with Sligo Rovers. McGuinness signed once again for The Hoops in November 2012.
McGuiness signed for another of the big 4 Dublin clubs, Street Patrick"s Athletic, on the 11th November 2014.