He authored the 2010 Conservative Party Manifesto titled 'An Invitation to Join the Government of Britain'.

[2] A former Downing Street aide, he was Director of Policy to Prime Minister David Cameron from May 2010 to October 2011.

Following the general election in May that year he led the development and implementation of the Programme for Government in the Conservative-Lib Dem Coalition.

Created a life peer on 1 October 2015, he took the title Baron O'Shaughnessy, of Maidenhead in the Royal County of Berkshire,[3] before being appointed as Parliamentary Under Secretary of State at the Department of Health and Social Care and as a Lord-in-Waiting (i.e. Government Whip in the House of Lords) on 21 December 2016.

[6] In May 2023, he published the O'Shaughnessy Review of Commercial Clinical Trials in the United Kingdom, which was commissioned by HM Government in February of that year.