McKean graduated from the University of Chicago with a BA/MA in Linguistics. As an undergraduate, she worked in a junior capacity on the Chicago Assyrian Dictionary. McKean has also served on the Visiting Committee to the University of Chicago's Regenstein Library and helped organize a dictionary-themed exhibit, The Meaning of Dictionaries, there in 2007.
McKean is a founder of Reverb, which makes the online dictionary Wordnik. She was previously the editor in chief of US Dictionaries for Oxford University Press and Principal Editor of The New Oxford American Dictionary, second edition.  McKean is the author of seven books:
- Weird and Wonderful Words (illustrated by Roz Chast, with an introduction by Simon Winchester, Oxford, 2002)
- More Weird and Wonderful Words (illustrated by Danny Shanahan), Oxford, 2003)
- Totally Weird and Wonderful Words (Oxford, 2006)
- That’s Amore (Walker & Company, 2007)
- The Secret Lives of Dresses (Grand Central, 2011)
- Aftercrimes, Geoslavery, and Thermogeddon: Plus 157 More Words From a Lexicographer's Notebook (TED Books, 2011)
- The Hundred Dresses (illustrated by Donna Mehalko, Bloomsbury, 2013)
McKean is also the editor of VERBATIM: The Language Quarterly, and edited a collection of work from that publication, "Verbatim: From the bawdy to the sublime, the best writing on language for word lovers, grammar mavens, and armchair linguists" (Mariner Books, 2001). McKean's novel The Secret Lives of Dresses was a best-seller in Australia, and has been optioned for film. She writes about dresses in her blog, A Dress A Day.
She wrote frequently for the "The Word" column in The Boston Globe. from 2008 through 2011 and wrote The Week in Words for the Wall Street Journal from 2011 through mid-2013. She has also written for the New York Times On Language column.
McKean's 2007 TED talk, Redefining the Dictionary, was the genesis for the founding of Wordnik.com. She has also spoken at Pop!Tech, Gel conference, Thinking Digital, and gave a Wordnik demo at the All Things Digital D8 conference in 2010. McKean sews her own clothes and often makes "stunt dresses" for speeches, including the Tetris-themed dress she wore to speak at the Web 2.0 Summit in 2009.
"Prettiness is not a rent you pay for occupying a space marked ‘female'.", a quote from McKean's blog, A Dress A Day, has been widely shared on social media. Since the original post features a large picture of Diana Vreeland, the quote has occasionally been misattributed to her. 
- "Normblog". 2007-01-19.
- "Erin McKean Biographical Information".
- "University of Chicago Magazine". 2006-10-01.
- "Libra: Library Reports and Announcements". 2006.
- "The Chicago Maroon". 2007-06-01.
- "Xconomy". 2013-03-12.
- "New York Times, "Wordsmiths: They Also Serve Who Only Vote on ‘Ain’t’"". The New York Times. 2006-12-23.
- Erin McKean, ed. (May 2005). The New Oxford American Dictionary (2nd ed.). Oxford University Press. p. 2051. ISBN 0-19-517077-6.
- "World Wide Words". 2002-12-14.
- "How Erin McKean Sold Her Blog-Based Book". MediaBistro. 2008-11-07.
- "If.com.au". 2011-05-12.
- Chillax – If it works like a word, just use it. Boston Globe 2008-08-03
- "Wall Street Journal". The Wall Street Journal. 2013-05-24.
- McKean, Erin (2009-12-17). "On Language: Redefining Definition". The New York Times.
- Wikimedia Foundation contributors (2009-02-26). "Advisory Board – Wikimedia Foundation". Wikimedia Foundation. Retrieved 2009-03-20.
- "Credo Reference".
- "TED blog". 2009-06-08.
- "Pop!Tech". 2006.
- "Erin McKean at GEL 2006". 2006.
- "Erin McKean at Thinking Digital 2011". 2001.
- "D8 Tech Demo: Wordnik". 2010-06-03.
- "Wardrobe Wrap of the Web 2.0 Summit". 2009-10-29.
- "STC Spotlight: Erin McKean, Honorary Fellow and the Summit’s Keynote Speaker". The New York Times. 2010-04-09.
- "A word to the wise". (12 August 2008). The Globe and Mail (Toronto, Canada), pp. A14.
- "Erin @ A Dress A Day".
- ""You don't owe prettiness to anyone"". 2013-08-12.
- Media related to Erin McKean at Wikimedia Commons
- McKean’s biography as member of the Wikimedia Advisory Board