Harlequins RL McDermott had spells on the coaching staff at
Super League clubs
Huddersfield and
Leeds before accepting his first top-flight head coaching role at
Harlequins in July 2006, replacing
Tony Rea. McDermott won his first match as a head coach against
Castleford. He went on to claim five wins and four losses in the remainder of 2006. McDermott remained at Harlequins for a further four seasons but the team decreased in performance. The team which had been in the top 5 in the year before McDermott's arrival finished 7th, then 9th then 9th again. Harlequins RL went on three long streaks of very poor form in the last season and a half of McDermott's tenure. The 2009 saw a second half of the season collapse with the team winning only 1 of its last 12 games and finishing 11th. The 2010 season saw an early win against
Catalans Dragons, but again only one win in the first 11 games. There were quite a few big losses by scores such as 62–4, 58-0 and 52–12. After a midseason streak of four wins in five games, the team again returned to losing form, losing 7 out of the last 9. McDermott had not secured the team's better players to new contracts, such as
Louie McCarthy-Scarsbrook, Will Sharp, Danny Orr, Oliver Wilkes and Luke Williamson and the team had finished 11th and 13th in successive seasons.
Leeds Rhinos McDermott left Harlequins and returned to Leeds as Assistant Manager at the end of the 2010 season. On 25 October 2010, following the resignation of incumbent coach
Brian McClennan, it was announced that McDermott would take over as head coach at Headingley on a three-year contract. McDermott coached Leeds to the
2011 Challenge Cup Final defeat by
Wigan at
Wembley Stadium. However, McDermott guided Leeds to
2011 Super League Grand Final victory over
St. Helens at
Old Trafford, after finishing in 5th place in the league. McDermott replicated the same feat in 2012, where Leeds won the World Club Challenge against
Manly. He coached
Leeds to their
2012 Challenge Cup Final defeat by
Warrington at
Wembley Stadium. Two months later, the two sides met again in the
2012 Super League Grand Final which Leeds won for the sixth time in nine years with the victory over Warrington at
Old Trafford their first
Challenge Cup win since 1999. They were knocked out of the playoffs against
Catalans Dragons after finishing 6th in the league, their worst position since 1996. In 2015 McDermott coached Leeds to a historic treble, winning the
Challenge Cup 50–0, scoring a last second try against
Huddersfield to win the
League Leaders' Shield, and beating
Wigan in a major final for the first time by 22–20 in the
2015 Super League Grand Final victory at
Old Trafford. McDermott was a nominee for the
BBC Sports Personality of the Year Coach Award at the end of the season. Leeds endured a difficult season in 2016 as they were flooded out of their training ground for the first half of the season and suffered a run of injuries that left them having to fight against relegation in the Qualifiers. At the start of 2017, with only the addition of
Matt Parcell to the Leeds squad from the previous year, they finished runners up to
Castleford in the table. They then beat Castleford in the
2017 Grand Final at
Old Trafford, with long-serving players
Rob Burrow and
Danny McGuire leaving the club as champions. After a run of seven losses in a row, the club sacked McDermott as head coach in July 2018.
Toronto Wolfpack McDermott took over at the
Toronto Wolfpack ahead of the
2019 RFL Championship season.
Oldham RLFC On 5 July 2021 it was reported that he had joined
Oldham as a coaching consultant to Brendan Sheridan, following the departure of former head coach
Matt Diskin in June.
Featherstone Rovers It was reported on 22 October 2021 that he had taken over as head-coach from
James Webster Newcastle Knights McDermott became assistant coach at the
Newcastle Knights in November 2022, ahead of the
2023 NRL season in Australia. ==International==