After graduating from university in 2008, Blenkinsop began working for the Labour Party as an international projects assistant and then international coordinator.
In 2013 he moved to lobbyists Centreground Political Communications and then in 2014 he joined Bell Pottinger as a consultant. Blenkinsop's job was declared on his brother's Register of Members' Financial Interests due him being 'engaged in lobbying the public sector on behalf of a third party or client'.
Blenkinsop stood in the 2014 London council elections as the Labour Party candidate for Knightsbridge and Belgravia Ward. With the top three elected, Blenkinsop came fourth - the highest place non-Conservative Party candidate, in what is traditionally a Conservative dominated council.
- Linkedin Joseph Blenkinsop, accessed 23 July 2015.
- Parliament Publications Register of Members’ Financial Interests as at 13 July 2015, accessed 23 July 2015.
- Westminster.Gov City council election results 2014, accessed 23 July 2015.