Glenn is an agile goalkeeper, who commands his area extremely well. He started his career at Leyton Orient and was part of the side that beat Northampton Town at the Millennium Stadium to win the Football League Youth Alliance Cup in 2001. He made his senior debut against Dagenham and Redbridge in an LDV Vans Trophy first round tie in October 2001 whilst still a scholar and also played in the final two games of that season’s Division 3 campaign. During the 2002-03 season, Glenn was one of the Os’ first choice keepers and his displays reaped a double reward as he signed full pro forms in the March and was named the club’s “Young Player of the Year” a short while after.
He began the following season as first choice at Brisbane Road, but a red card against Cheltenham Town in late August saw him lose his place and he didn’t play again until three months later against Cambridge United. The following week, it took just 16 minutes for him to experience déjà vu as he was dismissed against Cheltenham, this time in an FA Cup second round tie. He retained his “Young Player of the Year” trophy that season and followed that up with 17 league appearances in 2004-05, but injury limited him to just nine appearances across the next two seasons. Glenn started the 2007-08 season as second choice behind Stuart Nelson and, apart from a four-game stint in late November / early December, didn’t appear until the beginning of March, after which he retained his spot until the season’s end. Glenn played 45 more times for the Os’ before being released at the end of the 2009-10 season.
In the summer of 2010, he joined Southend United, who were newly-relegated to League 2 and, having made his debut against Stockport County on the opening day of 2010-11, finished the campaign having made 37 appearances in all competitions. The Shrimpers began the 2011-12 season well and Glenn had produced a number of solid performances before picking up a thigh injury against Torquay United in late October. He returned to action in early January, but made just five more appearances before reinjuring his thigh at the end of the following month. Glenn regained his place in the Shrimpers’ matchday squad on the final day of the “regular” season, when victory over Macclesfield Town sealed fourth spot and a play-off place; the subsequent two-legged semi-final was lost to Crewe Alexandra, but he had to watch from the bench as an unused substitute in both matches.
Glenn was allowed to leave Roots Hall in the summer of 2012 and played as a trialist for financially-stricken Portsmouth in a pre-season friendly against Aldershot Town after which his friendship with Shots goalkeeping coach (and ex-Orient team-mate) Ashley Bayes saw him sign on at the EBB Stadium as back-up to Jamie Young in the absence of the injured Ross Worner. He made his Shots debut at Exeter City in a Johnstone’s Paint Trophy southern section (west) first round tie in early September and made some good saves in normal time before saving two penalties as a 4-3 shoot-out win was secured. Due to the form of Jamie Young, Glenn only managed five appearances in 2012-13, a season that ended in the Shots getting relegated out of the Football League.
Shortly after the season’s end, the club entered administration, an event that resulted in the bulk of the playing staff either not being offered a new contract (as in Glenn’s case) or being made redundant. To his credit, he trialled back with the Shots and, on the club exiting administration (late in the July), earned himself a new one-year deal.