In his role as head of the political section of the Conservative Research Department, he helped prepare Hague for Prime Minister's Question Time and briefed the Shadow Cabinet for media appearances.

[7] At the 2001 general election, Glen stood in Plymouth Devonport, coming second with 27.1% of the vote behind the incumbent Labour MP David Jamieson.

[8][9] Following the election, he took an MBA at Fitzwilliam College, Cambridge,[10] and worked in the oil and gas industries in the UK and in the United States.

[14] Glen was criticised in April 2012 by campaigners for employing an intern from a charity that had recently sponsored an event where a "cure" for homosexuality was discussed.

[16] The paper advocated encouraging universities to build up endowments, which could then replace income from grants; reforms to the tuition fee cap towards "total course costs" instead of per-year caps, and allowing fee differentials by subject group; changes to the way in which research funding is allocated; and administrative savings by the Research Councils and the Office of Fair Access.

[16] He wrote an op-ed for the Daily Telegraph about the policies advocated in the paper, titled "Tuition fees cannot be the last reform of university funding".

[22] Despite describing himself as a Eurosceptic, Glen was a "reluctant Remainer" prior to the 2016 referendum as he did not feel it was the right time for the UK to leave the European Union.

[33] Glen played a significant contributory role[34] in the APPG Hunger and Food Poverty's inquiry, Feeding Britain.

[36] His website lists his further APPG memberships as: Archives and History, British Council (Appointed Secretary in 2011), British-Maldives Parliamentary Group, Complex Needs and Dual Diagnosis, Constitution, Parliament and Citizenship, Historic Churches, Malaysia, Nuclear Energy, Runaway and Missing Children and Adults, Suicide and Self Harm Prevention, and Voice UK.

[42] Tim Montgomerie, editor of ConservativeHome,[43] has described John Glen as a "full spectrum Conservative" – meaning one who is Eurosceptic and supportive of low taxation, but also concerned with social issues and the environment.

[44] Glen took part in the APPG on Hunger and Food Poverty inquiry, and argued in 2014 that prosperity needs to be shared, and that the Department for Work and Pensions should improve benefit payment reliability to prevent the need for foodbank use.

[48] On anti-mitochondrial donation therapy, Glen described himself as "instinctively cautious about technologies that, while noble in intent, could potentially open the door to the development of 'genetically modified babies'".