[2] Aged 16 he had a trial with Manchester United, but turned them down as he thought he was more likely to make it as a footballer with Hearts than with the Old Trafford club.
[3][4] Highly rated by the Hearts coaching staff,[5] Glen earned his first involvement with the first team squad when he was an unused substitute in a league match at Motherwell on 5 March 2007.
[11] On 3 May 2008 edition of 'Soccer AM', Glen and fellow Hearts youngster Matej Rapnik, appeared on the sub program, 'Skill Skool', where they went head-to-head in a battle of skill.
[13] Glen was accused of lacking a good attitude toward his game by manager Csaba László and consequently failed to become a regular in the Hearts team during season 2008–09.
Glen was offered to go on loan to Brechin City to gain experience but turned this down, preferring to stay with Hearts.
[21] In December 2011, with Hearts experiencing financial difficulty, Glen was told that he was free to either find a new club in the January 2012 transfer window, or he would be released when his contract expires in summer 2012.
[30] Glen was released by Ross County on 16 May 2014 after finding his first team opportunities limited, making just 15 appearances in the 2013–14 season.