He served as Parliamentary Under-Secretary of State for Biosecurity, Animal Health and Welfare from 2023 to 2024 in the Sunak ministry.

[5][6][7] From 2015 to 2022,[1] Douglas-Miller was the chairman of the Atlantic Salmon Trust, which had Prince Charles as its patron and Alister Jack as a board member.

[8] On 1 December 2023, Douglas-Miller was appointed Parliamentary Under-Secretary of State for Biosecurity, Animal Health and Welfare, a junior ministerial office in the Department for Environment, Food and Rural Affairs, succeeding Lord Benyon in the Sunak ministry.

[11] On 11 December, he announced that legislation would be introduced for the option to issue fixed penalty notices for various animal health and welfare offences, stating "I welcome penalty notices as an additional tool for our partners to use to encourage compliance with the law.

[14] Douglas-Miller was appointed Officer of the Order of the British Empire (OBE) in the 2021 New Year Honours for services to wildlife conservation in Scotland.