McDermott has held coaching positions at some of Asia's biggest clubs;
Al Ain (Abu Dhabi),
Esteghlal (Tehran) and
Al-Nasr (Dubai). Previously he was the fitness coach of the
Iran national football team during their successful World Cup 2014 qualification campaign. Prior to his second spell with the Iran national team, on 2 July 2017 he was appointed as the assistant manager of Esteghlal. After a brief spell as interim manager, on 30 October 2017 he terminated his contract by mutual agreement. After leaving Esteghlal he returned to the Iran national team to work alongside
Carlos Queiroz as an assistant coach for the
2018 FIFA World Cup and the
2019 AFC Asian Cup where they were knocked out in the semi-final by Japan. When Queiroz became the head coach of
Colombia in February 2019 it was announced that McDermott would join him but an agreement was not reached with the Colombian FA. On 31 March 2019, McDermott took the job of
Glentoran manager. Interim manager
Gary Smyth, who could no longer fulfil the role due to a lack of necessary UEFA coaching qualifications, returned to his former role as assistant. In his first full season as Glentoran manager, McDermott managed the club to victory in the Irish Cup final, defeating
Ballymena United 2–1 and thus securing a place in the
2020-21 Europa League preliminary round. McDermott strengthened the squad ahead of the 2020-21 season, signing former
Northern Ireland international
Luke McCullough and
Gibraltar goalkeeper
Dayle Coleing, as well as
Burundi midfielder
Gaël Bigirimana. McDermott's side defeated Faroese side
Havnar Bóltfelag 1–0 in the preliminary round, before being knocked out in a 5–1 defeat away to Scottish team
Motherwell. He was replaced by assistant manager
Rodney McAree as manager on 17 January 2023 after a poor run of form. After spending time as the assistant manager of the
Qatar national team, McDermott was named manager of
League of Ireland First Division club
Cobh Ramblers on 4 December 2024. On 19 May 2025, he guided his side to a 2–0 win over
Rockmount at
Turners Cross to win the
Munster Senior Cup. On 20 October 2025, it was announced that McDermott had departed the club, just days before the Promotion Playoffs began, having finished 2nd in the league. ==Personal life==