Career
Forster has also previously played for Berwick Rangers and East Fife on loan. Forster was in the Celtic youth system, but moved to Hibernian in 2010 after he was advised by Celtic that he would be unlikely to earn a professional contract with them. Hibs loaned Forster to Berwick Rangers during the second half of the 2011-2012 season.
Forster and Hibs agreed a one-year contract in May 2012 and he was loaned to East Fife for the first part of the 2012-2013 season.
Manager Pat Fenlon said that younger players, including Forster, would feature more in the 2013-2014 season. Fenlon praised the way that Forster had dealt with the physical presence that Hearts had in their attacking line.
Forster also played in the 2013 Scottish Cup Final defeat by Celtic, replacing injured captain James McPake. He signed a new one-year contract with Hibs in June 2013.
Six months later, Forster signed a contract with Hibs that is due to run until 2016.
On 12 January 2016, Forster completed a loan move to League Two side Plymouth Argyle until the end of the season.