Best known for her role in the Jarrow Crusade or as minister of education in the post-war Attlee government, Ellen Wilkinson’s pre-Jarrow parliamentary career has often been subject to only cursory academic attention. However, her time as Labour MP for Middlesbrough East between 1924 and 1931 is important for two reasons: not only did it help Wilkinson attain a national profile, but it showed that the Labour Party was making inroads in previously Liberal territory. This article is the first to concentrate solely on her tenure in Middlesbrough East. It will argue that Wilkinson was the first successful socialist missionary in Middlesbrough; one who challenged the fragile dominance of the Liberal Party and its cheerleaders in the local press, and whose success in two general elections showed that industrial towns such as Middlesbrough were growing increasingly receptive to the Labour Party. By engaging with Wilkinson’s tenure as MP for Middlesbrough East at a predominantly local level, this article is primarily focused on Wilkinson’s relationship with Middlesbrough and its inhabitants, and an examination of the constituency work of an early Labour Member of Parliament.