Following Steve Davis' sacking as head coach on 14 November, Brill was named interim head coach alongside Ross Embleton. After Justin Edinburgh was appointed head coach later that month, Brill became a member of the playing staff, making his debut for the club on 2 December in a 1–0 away defeat to Solihull Moors. He signed a two-year contract extension in February 2018 after he kept five clean sheets in 14 appearances up to that point in 2017–18. He finished the season with 29 appearances for Leyton Orient and was replaced as goalkeeping coach in July, allowing him to focus on his playing career. The following season, Brill was ever-present in league competition and kept 24 clean sheets in all competitions, equalling the club record, as Leyton Orient won the National League title and promotion to League Two. Ahead of the 2019–20 season, Brill signed a one-year contract extension with the club. After making 20 appearances in the first half of the season, with 19 of those appearances coming in the league, he sustained an injury in late December 2019 and announced his retirement from playing on 24 January 2020 to rejoin the club's coaching staff. Luton Town  Inverness Caledonian Thistle  Leyton Orient