After school, he worked in Canada and Australia between 1978 and 1988, initially in farming but later buying and selling a variety of businesses.

[5][6] In 2006, he founded the Public Interest Foundation, a grant-giving charity primarily focused on education and communities.

The aim of NIOT is to boost the quality of teaching and school leadership by carrying out research applying these insights to its professional development programmes, and sharing findings with the sector.

[25] Agnew became Minister of State for Efficiency and Transformation jointly at the Cabinet Office and HM Treasury on 14 February 2020.

[26][27] In April 2021 he was accused of a conflict of interest over his shares in Public Group, a firm helping companies bid for government contracts.

[28] On 24 January 2022, Agnew resigned as Minister of State for Efficiency and Transformation after strongly criticising the government's failure to tackle billions of pounds worth of fraud in the Coronavirus Bounce Back Loan Scheme.

Agnew accused the government of making "schoolboy errors" through giving loans to more than 1,000 companies which were not trading when the pandemic happened.