A right-handed batsman and right-arm seam bowler, Gregory made his senior cricket debut in 2010, representing Somerset against the touring Pakistanis.

[5] In July 2008, Gregory was selected to represent the 'South and West' in the England and Wales Cricket Board (ECB) Regional Under-17 Festival, and scored a half-century in the first of his three matches.

[15] 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.

[18] Gregory received his first call-up to the England squad for the one-off One Day International (ODI) against Ireland in May 2015, but he did not play.

[24][25] 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.

[26][27] On 17 June 2020, Gregory was included in England's 30-man squad to start training behind closed doors for the Test series against the West Indies.

[28][29] 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 (ODI) series against Ireland.