Gregory represented Devon County Cricket Club at youth level, playing Under-13, Under-14, Under-15 and Under-17 cricket for the county. He made his club debut at the top level of club cricket, playing in the Devon Cricket League in 2006 at the age of 14, scoring 28 runs for Plympton Cricket Club. Throughout 2006 and 2007, he played primarily as a batsman, bowling infrequently and in short spells when he did so. In 2008, his bowling workload increased dramatically, and he finished the season with 20 wickets at an average of 17.40 for Plympton. In July 2008, Gregory was selected to represent the 'South and West' in the England and Wales Cricket Board Regional Under-17 Festival, and scored a half-century in the first of his three matches. The 2008 season also saw Gregory make his debut in the Minor Counties Championship for Devon, and play his first match for Somerset County Cricket Club, a Second XI contest against the Marylebone Cricket Club Young Cricketers in which he scored 87 runs in Somerset's only innings. Gregory was Plympton's leading bowler in 2009, claiming 36 wickets at an average of 13.61, including two five-wicket hauls. He continued to play for Somerset Second XI, and occasionally for Devon throughout 2009 and 2010.
One-day debut
Following a string of good performances for England Under-19s and Somerset Second XI, including a hat-trick against Essex Second XI, Gregory made his List A debut for Somerset against the touring Pakistanis. He claimed four wickets in the match, before being bowled for a duck in Somerset's reply.
Gregory made his international debut for England Under-19s during their series against the touring Sri Lanka Under-19s. He claimed four wickets in two four-day matches against the tourists. He performed better in the shorter formats of the game, scoring 55 runs and sharing a 103-run partnership with Joe Root to orchestrate victory in the second Twenty20. In the second one-day match, he top-scored for England with 87, but despite claiming 1/16 in an economical bowling spell, he could not prevent Sri Lanka winning with over 15 overs to spare. Gregory was named as captain of the England Under-19s for the tour of Sri Lanka in January 2011. Gregory received his first call-up to the England squad for the one-off One Day Internationalagainst Ireland in May 2015, but he did not play. In July 2019, Gregory was named in England's Test squad for the one-off match against Ireland at Lord's, having also captained the England Lions against Australia A earlier in the month. However, he did not play in the Test against Ireland. In September 2019, he was named in England's Twenty20 International squad for their series against New Zealand. He made his T20I debut for England, against New Zealand, on 1 November 2019, although he did not bat or bowl. In the second match of the series against New Zealand, Gregory became the second bowler for England to take a wicket with his first delivery in a T20I. On 29 May 2020, Gregory was named in a 55-man group of players to begin training ahead of international fixtures starting in England following the COVID-19 pandemic. On 17 June 2020, Gregory was included in England's 30-man squad to start training behind closed doors for the Test seriesagainst the West Indies. On 9 July 2020, Gregory was also included in England's 24-man squad to start training behind closed doors for the One Day International series against Ireland. On 27 July 2020, Gregory was named as one of three reserve players in England's squad for the ODI series.
