The group was formed as part of a coalition between the Anti-Nazi League and the National Assembly Against Racism, the TUC and leading British unions such as T&G (now Unite) and UNISON in response to electoral successes by the BNP.
Its chairman is the former Labour Party Mayor of London, Ken Livingstone, and its joint secretaryship is shared by Weyman Bennett, the national organiser of the Anti Nazi League and a member of the central committee of the Socialist Workers Party, and Sabby Dhalu, formerly of the National Assembly Against Racism (NAAR).
The organisation has signatories and members from across the political spectrum including MPs from all of Britain’s leading political parties and a number of members of the Labour cabinet. Other notable signatories include Holocaust survivor Henry Guterman.
At Unite Against Fascism's 2007 national conference, speakers ranged from cabinet minister Peter Hain to Edie Friedman of the Jewish Council for Racial Equality (JCORE) and Dr. Muhammad Abdul Bari from the Muslim Council of Britain, as well as figures from the major UK trade unions.
Unite Against Fascism often organises large protests against the BNP including outside the trial of BNP leader Nick Griffin and Mark Collett on race hate charges at Leeds Crown Court. Unite Against Fascism also jointly called the rally of over 1,000 people when Nick Griffin and holocaust denier David Irving spoke at the Oxford Union in November 2007
The anti-fascist magazine Searchlight disaffiliated from UAF after an argument over tactics to defeat the BNP.