He started his career with Boyle Celtic then joined Belvedere at under 15 before moving to Millwall, for whom he played as a substitute in the 2004 FA Cup Final, and making 24 appearances for in the Football League. In August 2006, Cogan signed for Barnet playing one season playing 39 appearances and scoring three goals in League Two, before being signed by Ronnie Jepson for Gillingham in June 2007. He was loaned to Grays Athletic in March 2008, scoring five goals in 13 Conference National appearances. Cogan signed for Grays permanently in July 2008 following his release from Gillingham. He then moved to Crawley Town in June 2009, after Steve Evans had tried to sign him the previous season. Cogan left Crawley in November 2010 by mutual consent, joining Dover Athletic a few days later.