Professor Yankah hold degrees from the University of Michigan, Columbia Law School and Oxford University. His work focuses on questions of criminal theory and punishment and political theory and particularly, questions political obligation and its interaction with justifications of punishment. Consequently, he has also written on questions of race, equality and moral values in areas ranging from policing to education and athletics. His work has appeared in philosophy journals, law review articles, peer reviewed legal theory journals and books. He has been a special invited scholar for the McArthur Foundation and in Spring 2016 was a Visiting Fellow at the Institute for Advance Studies at the University of Jerusalem.

His interests have also led him to develop expertise in voting rights and election law and he serves as the co-chair of the New York Democratic Lawyers Council, the voting rights arm of the New York Democratic party, the coordinating arm of the DNC believed to be the largest voting rights group in the country. He sits on the Board of the Innocence Project and has served on the Board of the American Constitution Society (NY Chapter). He have written for publications spanning The New York Times, The New Yorker and The Huffington Post, among others and has been a regular commentator on criminal law issues on television and radio including MSNBC, BBC and BBC International.