Rusk was appointed U23s Head coach in March 2015, stepping up from his role as U18s coach. In February 2016, he was promoted to first-team coach by Chris Hughton until the end of the season, replacing the outgoing Nathan Jones. In the sixteen remaining games of the season, they lost just once as they sealed third-place in The Championship, missing out on automatic promotion by goal difference. In the first year of Premier League 2's current format - he guided the Seagulls to an 8th-placed finish and reached the last sixteen of the EFL Trophy. The following year, his side finished third in the league and won promotion to Premier League 2Division 1 - the highest level for U23s football - for the first time ever, following a 2–0 victory over Aston Villa in the play-offs. The 2018–2019 season saw a string of impressive results, including a 5–0 win over Manchester City , as they went unbeaten in their first six games. Rusk's side finished the season in third-place, higher than a number of established academies, including Chelsea, Liverpool, Tottenham and West Ham. Despite losing a number of key players to the senior squad in 2019–20, the side continued their good form and reached the knockout stages of the EFL Trophy for a second time under Rusk's management.
He left Boston to join Northwich Victoria on a free transfer on 2 July 2007, being signed by former Boston teammate Neil Redfearn. Rusk scored on his debut for Northwich, in the 2–1 loss against Ebbsfleet United, which was the first game for Ebbsfleet under this name, having previously been known as Gravesend & Northfleet. In September 2007, Rusk was placed on the club's transfer list and joined Rushden & Diamonds on a one-month loan later that month.
Manager Dino Maamria confirmed in January 2008 he was to move, with Weymouth believed to be his next destination. However, he signed a one-and-a-half-year contract with York City on a free transfer on 8 January. He made his debut in the team's 2–0 win against Aldershot Town in January and finished the season with 14 appearances for the club. He suffered a medial knee ligament injury during York's 1–1 draw with Torquay United on 28 August, which saw him substituted for Niall Henderson in the 73rd minute. He made his return on 20 September in a 1–1 with Salisbury City. He scored the winning penalty for York in a 4–2 penalty shoot-out victory against Mansfield Town in the Conference League Cupthird round on 4 November, which finished 1–1 after extra time. He started in the FA TrophyFinal at Wembley Stadium on 9 May 2009, which York lost 2–0 to Stevenage Borough. He was released by York following the end of the 2008–09 season, during which he made 47 appearances and scored one goal.
Rusk joined Conference Premier team Crawley Town on 27 May 2009. He made his debut as a 22nd-minute substitute in a 4–0 defeat against Mansfield Town. Rusk went on to feature regularly during his first season for the club, making 42 appearances, many of which were at right-back. He was offered a new one-year contract in April 2010, which he signed in May. In February 2011, Rusk was an 81st minute substitute in Crawley's 1-0 FA Cup defeat to Manchester United at Old Trafford. Due to a number of serious injuries, he retired following the end of the 2010–11 to take a role with Crawley's Centre of Excellence ahead of their first season in the Football League. He was appointed a youth team coach at Brighton & Hove Albion on 6 March 2012, a role involving overseeing the development of the club's scholars and managing the under-18 team.
International career
Despite being born in England, Rusk was capped three times by the Scotland national under-18 team.
