[4] He is founding editor of a book series entitled Routledge Philosophers,[5] and (with Leslie Green) of Oxford Studies in Philosophy of Law.

[6] Leiter was also the founder and for 25 years the editor of the Philosophical Gourmet Report ("PGR"), an influential but also controversial ranking of philosophy PhD programs in the English-speaking world.

[10] Cato Institute senior fellow Walter K. Olson described Leiter as "left-leaning" in his book Schools for Misrule: Legal Academia and an Overlawyered America (Encounter Books, 2011),[11] and Leiter himself has professed sympathy for Marx, stating in an interview, "On two central issues, Marx was far more right than any of his critics: first, that the long-term tendency of capitalist societies is towards immiseration of the majority (the post-WWII illusion of upward mobility for the 'middle classes' will soon be revealed for the anomaly it was); and second, that capitalist societies produce moral and political ideologies that serve to justify the dominance of the capitalist class.

Upon publication, Jeremy Horder wrote that the "book will confirm Brian Leiter's place in the front rank of legal theorists in the world today.

He has written a considerable amount on the philosophical work of Friedrich Nietzsche, including an article for the Stanford Encyclopedia of Philosophy.

"Every reader will learn something from this remarkable book, and, beginning now, every serious scholar of religious toleration will have to contend with Leiter's bold claims.

[24] Leiter has also published work on meta-ethics, social epistemology, the law of evidence, and on philosophers Karl Marx, Martin Heidegger, and Ronald Dworkin.

[28] The PGR was described by David L. Kirp in a 2003 New York Times op-ed as "the bible for prospective [philosophy] graduate students.

"[30] Carlin Romano, in America the Philosophical (Knopf Doubleday Publishing Group, 2013), referred to the PGR rankings as "often-criticized" and "biased towards mainstream analytic departments" although it covers Continental philosophy as well.

[34] In response, Leiter appointed a co-editor for the 2014 report Berit Brogaard, a philosophy professor at the University of Miami, and agreed to step down as editor after its publication.

Leiter's philosophy blog includes both professional news and polemics, for example, critiques of proponents of intelligent design[40] and of the 2003 invasion of Iraq.

[41] He has also written critiques of journalists and philosophers, including Carlin Romano,[42] Thomas Nagel,[43] Leon Wieseltier,[44] and Paul Campos.