In his first season as manager of Reading he led them into the quarter-finals of the FA Cup for the first time in 83 years, a run that included knocking out Liverpool at Anfield.

Born in Slough, Buckinghamshire,[1] McDermott joined Arsenal as an apprentice in January 1977, signing professional forms with the club in February 1979.

He was a regular in Arsenal's reserve team, finishing as top scorer in the Football Combination in 1978–79, before making his début as a substitute against Bristol City on 10 March 1979.

[9] Unable to match his goalscoring rate at the top level, he featured much less in the 1982–83 and 1983–84 seasons and was loaned out twice by the Gunners: once to Fulham in 1983 and then to IFK Norrköping between April and October 1984, where he was named Sweden's Player of the Year.

[10] McDermott secured a permanent move to Oxford United in December 1984, having made 72 appearances (44 starts, 28 as sub) for Arsenal, scoring 13 goals.

After a spell in Hong Kong for club South China, McDermott returned to England to play in the Sussex County League with STAMCO while working at Slough Town as Football in the Community Officer.

The Royals went on to beat Premier League side Burnley 1–0 thanks to a late strike from Gylfi Sigurðsson to secure a place in the FA Cup fifth round.

After a goalless first leg at the Madejski Stadium, striker Shane Long scored twice in a 3–0 win at Cardiff to give Reading a trip to Wembley for the Play-off Final on 30 May 2011, where his team lost 4–2 to Swansea City, managed by his old colleague, Brendan Rodgers.

[33] On 6 February 2013, McDermott was named Premier League Manager of the Month for January after guiding his side to victories over West Bromwich Albion and Newcastle United as well as a hard-fought draw with then third place Chelsea.

[36] McDermott stated that he would have initially waited until Summer 2013 to resume his managerial career but due to the status and position of the club decided to take charge with 5 games left of the 2012–13 season.

[38] By coincidence, the head coach of the high-profile local professional rugby league team, Leeds Rhinos was also called Brian McDermott.

[39] In the summer of 2013 McDermott updated the squad with £1 million midfielder Luke Murphy from Crewe Alexandra,[40] and defender Scott Wootton from Manchester United.

[41] He further added to this by completing several free transfers including forwards Noel Hunt and Matt Smith in July,[42] and Lithuanian international defender Marius Žaliūkas in late October.

[51] On 1 February, McDermott's Elland Road assistant Nigel Gibbs was named as caretaker manager for the club's home derby against Huddersfield Town.

[53] On 3 February, McDermott returned to the club and carried out first team training and a press conference announcing he had been reinstated after seemingly being sacked on 31 January by a lawyer.

McDermott proclaimed his love for the club and said the fans support for him in the 5–1 win against Huddersfield Town meant that he wanted to return to the role despite the uncertainty.

[61] On 30 May 2014, McDermott and Leeds United parted company with owner Cellino stating that he wanted a fresh approach, with a head coach rather than a manager.

[67] He then worked as a consultant for various organisations, including the League Managers' Association, before he was appointed director of football at Scottish club Hibernian in May 2023.