McWhorter was born and raised in Philadelphia. He attended Friends Select School in Philadelphia, and after tenth grade was accepted to Simon's Rock College, where he earned an A.A. degree. Later, he attended Rutgers University and received a B.A. in French in 1985. He received a master's degree in American Studies from New York University and a Ph.D. in linguistics in 1993 from Stanford University. After graduation he was an associate professor of linguistics at Cornell University from 1993 to 1995 before taking up a position as associate professor of linguistics at the University of California, Berkeley, from 1995 until 2003. He left that position to become a Senior Fellow at the Manhattan Institute, a conservative think tank, and a columnist for the New York Sun. Since 2008, he has been a lecturer at Columbia University.

He has published a number of books on linguistics and on race relations and makes regular public radio and television appearances on related subjects. He has spoken many times on National Public Radio and is an occasional contributor on Bloggingheads.tv. He has appeared twice on Bullshit!, once in the profanity episode in his capacity as a linguistics professor, and again in the slavery reparations episode for his political views and knowledge of race relations. He is also the author of the courses titled "Understanding Linguistics: The Science of Language" and "Story of Human Language" for The Teaching Company. His 2003 Authentically Black has been interview-reviewed on booknotes.org.