[2] Blenkinsop worked as a constituency researcher for Ashok Kumar, Labour MP for Middlesbrough South and East Cleveland, from 2002 to 2008.

[3][4] Blenkinsop was selected as the Labour candidate for Middlesbrough South and East Cleveland in April 2010, following Ashok Kumar's unexpected death the previous month.

[8][9] After he called for party leader Jeremy Corbyn's resignation in 2016, a Labour member was suspended and investigated by the police for allegedly threatening him.

[10] After the calling of the 2017 general election, Blenkinsop announced that we would not seek re-election as an MP as he could not stand as a Labour candidate whilst Corbyn served as party leader.

Blenkinsop returned to the Community union as a London-based project manager after leaving Parliament,[13] and became a public affairs advisor for the Federation of Small Business in 2020.