Whilst at Whitgift, he played with future Surrey teammate and England Test opener Rory Burns, who is the same age.

[6][7] Roy made no further appearances for the Surrey second team in 2007, but was selected to represent the South at Under-17 level in the ECB Regional Festival, held at Loughborough in July 2007, where he played in three matches, against the West, Midlands and North.

In his debut in the Second XI Championship, Roy scored 88 from 89 balls against a Hampshire attack which included the South African Test match bowler Nantie Hayward, having come to the crease with Surrey in trouble at 89–4.

His second match was disrupted by the weather and was declared a no result in the thirteenth over of MCC Universities' innings, which was being bowled by Roy.

Batting at number five, Roy was dismissed for a duck in Surrey's first innings, but fared better with the ball, taking 2 wickets for 51 runs from five overs.

However, on 25 April 2009, he reminded the county selectors of his ability while playing for his club, Reigate Priory, in a 50-over per side match against the Surrey Second XI.

He took a catch as Surrey were dismissed for 157, and opened the innings for Reigate Priory, scoring 69 runs from only 51 balls against a bowling attack including former England international James Ormond before being caught behind.

On 23 May 2009, Roy scored 115 off 88 balls in Reigate Priory's victory over Spencer in the Surrey Championship Premier Division.

Selected for Surrey to play against Warwickshire in the Under-19s County Championship at Whitgift School on 6 July 2009, Roy scored 129 from 106 balls in a drawn match.

After an unremarkable start to the season, Roy made his first significant contributions to the team in May, scoring centuries in three successive Championship matches, against Essex, Sussex and Durham respectively.

In Surrey's second innings, Roy batted at number five and came to the crease with the score 42/3 against a bowling attack containing internationals Yasir Arafat and James Kirtley.

[citation needed] Roy maintained his form with a century for Reigate Priory, but as the county schedule turned to a long period without Championship matches, he had no opportunity to continue the run.

[16][17] Surrey did not progress beyond the group stages of the 2010 Friends Provident t20, and Roy's personal performances also dipped towards the end of that competition.

During the match, Roy enjoyed a partnership of 105 runs in 17 overs alongside Surrey's new signing, England international Kevin Pietersen.

By the end of the 2010 season, Roy was established as a first team regular in all forms of cricket, and signed a two-year contract with Surrey, which he described as "a dream come true".

Surrey had strengthened their batting resources over the preceding winter, confirming the long term signing of Kevin Pietersen, as well as bringing in new batsmen Zander de Bruyn and Tom Maynard, and Roy began the season in the Second XI.

However, Roy was included in the first team for the Clydesdale Bank 40 competition and made an immediate impression, scoring 60 runs in his first match, against Scotland, and 76 against Hampshire.

[23] Roy's season ended in fine style, being part of the Surrey side who won the CB40 final at Lord's against Somerset.

[24] Although Roy's day wasn't a personal success - being dismissed for a typically aggressive 11 immediately before a rain delay - he could at least be content that, as the second highest run scorer in the competition[25] he had played a significant part in Surrey's progress to that stage.

In October 2018, he was named in Nelson Mandela Bay Giants' squad as their International Marquee player for the first edition of the Mzansi Super League T20 tournament.

[32][33] In September 2019, he was named in the squad for the Nelson Mandela Bay Giants team for the 2019 Mzansi Super League tournament.

[36] On 27 August 2020, Roy opted out of 2020 Indian Premier League for personal reasons and as a result he was replaced by Australian all-rounder Daniel Sams.

[44] He made his One Day International debut for England in a one-off ODI against Ireland at Malahide on 8 May 2015, but the match was abandoned due to rain.

[115] During England's win against the West Indies, Roy re-aggravated a hamstring injury he had been suffering with early in the season whilst fielding during the first innings.

Roy protested against his dismissal and failed to leave the playing area in a timely manner and he was subsequently fined 30% of his match fee and given two demerit points for dissent.

[120] Roy ran out Martin Guptill who was attempting to come back for a second run, off of Jofra Archer's final delivery of the super over.

His impact was felt in England's must-win games, against India and New Zealand in the round-robin, and against Australia in the semi-final, as he stitched together three successive century stands with his opening partner Jonny Bairstow.

Having scored 443 runs from seven innings at an impressive strike-rate of 115.36, Roy forms a formidable opening partnership with Rohit Sharma in this XI".

The good form of Dawid Malan, his replacement as opener in the team, saw Roy's place in the squad taken by Harry Brook.

[133] Roy took A-level examinations in Sports Science and Business in 2008, and was offered a place at St. Mary's University College, though he turned down the opportunity in order to concentrate on cricket.