[10] He played 28 games in the 2007–08 campaign, and was an unused substitute in the 2008 FA Trophy final, as Torquay lost 1–0 to Ebbsfleet United at Wembley Stadium.

[11] He was transfer-listed by manager Paul Buckle in June 2008,[12] but forced his way back into the first-team after Torquay made a bad start to the 2008–09 season.

[13] After forming a solid partnership with Chris Todd at the heart of defence, Torquay were promoted back to the Football League after beating Cambridge United 2–0 in the Conference National play-off final at Wembley.

In January 2012, Robertson signed a two-and-a-half-year deal with League One side Preston North End for an undisclosed transfer fee (later reported to be £60,000).

[22][23] He scored his first goal for the club on 14 April against Huddersfield Town, and after the game was praised by manager Graham Westley for his application and character.

[24] Due to the form of summer signings Paul Huntington and Shane Cansdell-Sherriff, Robertson had to wait until 14 October for his first league appearance of the 2012–13 season, when he put in a "terrific display" and again earned praise from Westley for his hard work and professionalism.

[25] He was limited to a total of 24 league starts over the course of the campaign, and decided to leave the club after failing to play at Deepdale under new boss Simon Grayson.

[27] Upon securing him to a two-year contract, manager Micky Adams noted that Robertson had experience of League One football and had made a good impression on him during his time at Torquay.

[29] On 1 April, he was sent off during a 2–1 win over Crawley Town after the referee mistakenly thought he had made a tackle from behind, when in fact the culprit was club captain Doug Loft.

[42] However, he was limited to just 19 appearances throughout the 2016–17 campaign, and manager Neal Ardley decided to release Robertson in May 2017 to allow a path to the first-team for youngster Will Nightingale.

[43] He signed with newly relegated EFL League Two club Swindon Town in June 2017; manager David Flitcroft stated that Robertson was a "solid character" and had "the profile of a centre-half that I was looking for".

[44] On 8 August 2017, he made his debut for Swindon during their EFL Cup first round tie against Championship side Norwich City, featuring for the full 90 minutes in the 3–2 defeat.

[46] He acted mainly as a back-up to Dion Conroy / Matt Preston and Olly Lancashire and ended the 2017–18 campaign with 22 appearances for the "Robins", having picked up an injury in mid-March.

[51] On 4 September 2019, Robertson joined Ilkeston Town of the Northern Premier League Division One South East, stating that the club was close to his home and young family.