McDermott began his career at Ashbourne United then moved to Cherry Orchard of Dublin, where he was scouted, and signed up by Manchester City.
[2] On 12 September 2008, McDermott joined Football League One side Milton Keynes Dons on a one-month loan deal.
Following his loan spell at Chesterfield ended, McDermott spent the next three months, playing for the Manchester City Elite Development Squad.
[17] McDermott made his debut for the club, coming on as a second-half substitute, in a 1–0 win against Queens Park Rangers on 30 January 2010.
[23] McDermott then scored his first goal for the club, in a 2–2 draw against Hartlepool United on 30 April 2011, resulting in them securing a League One play–offs place.
[25] McDermott recovered from his injury and returned to the starting line–up in the semi-final of League One play–offs against Huddersfield Town and scored his second goal for the club, in a 1–1 draw on 14 May 2011.
[26] In the return leg, he started the match and played 77 minutes before being substituted, as Bournemouth lost on penalties to Huddersfield Town after the semi-final finished 4–4 on aggregate.
[30] He made his Terriers debut, starting a match and playing 52 minutes before being substituted, in the 1–1 draw against Bury at the Galpharm Stadium on 6 August 2011 in the opening game of the season.
McDermott can put others in and also create opportunities for himself, but it's important he learns to do the right thing in the right areas of the pitch, because a couple of times at Port Vale, he got caught out.
[33] Ten days later on 30 August 2011, he scored his first goal for the club in the 2–1 win over Northampton Town at the Sixfields Stadium in the Football League Trophy.
[37] Manager Clark responded to his lack of first team opportunities, saying: "He has had to be patient and McDermott did lots of good things.
"[40] McDermott made his second debut for Bournemouth, starting a match and playing 68 minutes before being substituted, in a 2–0 win against Exeter City on 7 February 2012.
[48] Despite this, McDermott set up two goals, coming from the league against Notts County on 23 October 2012 and then from the FA Cup match against Dagenham & Redbridge on 3 November 2012.
In the 2013–14 season, McDermott continued to find his first team opportunities limited, as he found himself placed on the substitute bench.
[55] McDermott played in both legs of the UEFA Europa League second round against Hajduk Split, as Dundalk lost 3–2 on aggregate.
[59] After leaving Dundalk at the end of the 2014 season, McDermott returned to England, where he joined Salford City on 6 January 2015.
[67] McDermott made his debut for Rochdale, starting a match and playing 67 minutes before being substituted, in a 2–0 win over Peterborough United in the opening game of the season.
[68] Three days later on 11 August 2015, he scored his first goal for the club in the 45th minute against Coventry City in the first round of the League Cup and helped Rochdale win 5–3 on penalties following a 1–1 draw.
[76] It wasn't until on 5 March 2016 when McDermott made his return to the starting line–up against Coventry City, playing 60 minutes before being substituted, in a 1–0 win.
[83] McDermott made his return from injury against Chesterfield in the second round of the EFL Trophy, coming on as a 54th-minute substitute, in a 2–0 loss on 6 December 2016.
[91] After missing a match due to injury, McDermott made his debut for Swindon Town during their 1–1 home draw with Exeter City, featuring for 45 minutes before being replaced at half-time by Kaiyne Woolery on 12 August 2017.
[93] However, in a match against Barnet on 2 September 2017, he received a straight red card in the 50th minute for a foul on David Tutonda, in a 4–1 loss.
[94] After serving a three match suspension, McDermott made his return to the first team, coming on as a 59th-minute substitute, in a 2–1 loss against Coventry City on 26 September 2017.
[96] It wasn't until on 15 December 2017 when McDermott made his return to the starting line–up against Colchester United and played 68 minutes before being substituted, in a 3–2 loss.