Derby County

Guy came through the Derby County youth team from the age of nine to turn professional at the club in February 2015.^[4] He played all three Group Stage games for the under-23 team in the EFL Trophy during the 2016–17 season. He joined EFL League One club Port Vale on a half-season loan on 11 January 2017.^[5] Nine days later he was named as man of the match on his first-team debut for Port Vale in a 2–2 draw with Bury at Vale Park; his performance also saw him named in the Football League Paper's Team of the Week.^[6] Manager Michael Brown said, "I thought he mixed his game up well - short and long passes, broke it up, forward runs, wanting to do well".^[7] He was again named as Vale's man of the match after a shortage of defenders saw him play at right-back in a 2–1 home defeat to Bradford City on 25 February.^[8] However, he picked up a hamstring injury in mid-March, and was ruled out for the rest of the season.^[9]

Guy made his Derby debut on 12 September 2017, in a 3–2 defeat at Barnsley in the EFL Cup.^[10] On 12 January 2018, he returned to League One on loan at Bradford City on loan until the end of the 2017–18 season.^[11] "Bantams" boss Stuart McCall said that "[he will] give us a little bit extra depth. He is hungry enough, however, to want to push himself into the starting XI".^[12] It took until his tenth appearance for Bradford for him to be on the winning side, when he was named as man of the match during a 1–0 victory over Gillingham.^[13]

Blackpool

On 31 August 2018, Guy joined League One side Blackpool on a loan deal until the end of 2018, with the deal due to be made permanent in January 2019, at which point he would sign an 18-month contract with the option of a further 12 months on top of that.^[14] He scored on his Seasiders debut with a 25 yards (23 m) volley in a 3–3 draw with Macclesfield Town in an EFL Trophy group stage game on 4 September.^[15] The permanent deal was confirmed on 2 January.^[16] He ended the 2018–19 season with 24 appearances to his name. On 27 November 2019, he was sent off after receiving two bookings in a 3–1 defeat to Scunthorpe United at Bloomfield Road.^[17]

Carlisle United

On 30 January 2020, Guy signed an 18-month deal with EFL League Two side Carlisle United after moving for an undisclosed fee.^[18] Carlisle head coach Chris Beech told the club website that Guy was a "marquee signing".^[19] However, he picked up a knee injury in his third appearance for the "Blues" and was ruled out of action for the rest of the 2019–20 season after undergoing surgery.^[20]

Guy made 47 appearances in the 2020–21 season, helping the "Cumbrians" to a tenth-place finish. He made a total of 14 assists, more than any other player in League Two.^[21] He signed a new one-year deal in April, with director of football David Holdsworth keen to extend the deal even further.^[22] Guy was voted Carlisle United Player of the Year by News and Star readers, attracting 46% of the vote from more than 750 fans.^[23] His success carried over into the club's own awards as he picked up the main Player of the Year award.^[24]

Following the departure of captain Nick Anderton in July 2021, Guy was appointed club captain ahead of the 2021–22 season.^[25] He was a subject of interest for big-spending National League club Wrexham, but was praised by Beech for his commitment to Carlisle.^[26] He went on to sign a new deal at Carlisle in September to keep him at Brunton Park until summer 2023 (with a further 12-month option).^[27] However, Wrexham's interest continued into the January transfer window, forcing new head coach Keith Millen to deny reports that he would be forced to sell Guy.^[28] By March, Paul Simpson – yet another new head coach – confirmed that Guy had been ruled out for the rest of the 2021–22 season after suffering medial knee ligament damage.^[29]

He signed a new two-year deal, with an option, in March 2023.^[30] He made 52 appearances throughout the 2022–23 campaign, scoring four goals, including one in the play-off semi-final victory over Bradford City.^[31][32] Carlisle secured promotion by beating Stockport County on penalties in the final at Wembley Stadium; Guy played in the match, being substituted on 78 minutes.^[33]