This paper starts from the standpoint that academic freedom is a necessary precondition to sociological imagination that challenges and defies the status quo. In the introduction, we consider the legacy of sociology as praxis – intended not merely to understand, but to change the world. We then move on to conceptualise academic freedom as requiring formal, infrastructural and psychic freedoms. We then chart the genealogy of universities from academically free, but socially exclusive, institutions to their present state, using the history of higher education in the UK as a case study to consider the prospects for universities and academics within them to contribute to a vibrant and sustainable defiant sociological research imagination and the consequences of their failure to do so. We finish with a manifesto for the reinvigorating of a defiant sociological imagination building on the radical traditions we have referred to above.