McDermott joined Arsenal's youth team in July 2009 after a successful ten-day trial with the club as a 15-year-old in May 2008.

McDermott signed for Arsenal from Kristiansand minnows IK Våg in November 2008, but didn't officially complete his move to the club until after he turned 16 at the end of May 2009.

[3] McDermott was released by Arsenal in the summer of 2012,[4] before he signed with Norwegian club Sandnes Ulf on 15 August 2012.

[2] He made his debut in Tippeligaen in the match against Rosenborg on 19 October 2012, instead of the first-choice goalkeeper Aslak Falch.

[6] Sandnes Ulf were relegated in 2014, but in the summer transfer window of 2015, McDermott returned to the first tier as he joined IK Start.