[1] Born in Kingston upon Thames, Douthwaite attended Reed's School in Cobham, Surrey, then went on to Cardiff Metropolitan University, where he earned a degree in Sports Management.
[1][2] He made his List A debut for Warwickshire against the West Indies A team in a tri-series warm-up match on 17 June 2018.
[3] He made his Twenty20 debut for the Marylebone Cricket Club in the 2018 MCC Tri-Nation Series against the Netherlands on 29 July 2018.
[4] He made his first-class debut on 26 March 2019, for Cardiff MCCU against Somerset, as part of the Marylebone Cricket Club University fixtures.
[6] Prior to being signed by Glamorgan, Douthwaite had scored his maiden century in first-class cricket,[6] with 100 not out from 107 balls for Cardiff MCCU against Sussex.