McLean is best known as the co-author, with Fortune colleague Peter Elkind, of The Smartest Guys in the Room (ISBN 1591840082), exposing the corrupt business practices of Enron officials. The book was the result of her reporting on Enron for the magazine and she first wrote about Enron with her article in the March 5, 2001 issue of Fortune entitled, "Is Enron Overpriced?". The book was later made into the Academy Award nominated documentary Enron: The Smartest Guys in the Room. Her column, "The Bulldog", appeared regularly in Fortune. She joined Vanity Fair in 2008.

McLean grew up in Hibbing and received her BA in English and mathematics at Williams College in 1992. After college and prior to joining Fortune, she worked as an investment banker for Goldman Sachs.

McLean has made appearances on the The NewsHour with Jim Lehrer, acting as an observer of the trials of Ken Lay and Jeffrey Skilling.

McLean was also a guest on The Colbert Report on October 13, 2008, a guest on The Daily Show with Jon Stewart on January 15, 2009 and was interviewed on the PBS program NOW with David Brancaccio on January 30, 2009.

She is writing a book with Joe Nocera on the 2008 financial crisis. The book, titled All the Devils Are Here, is set to be published in November 2010 by Portfolio.

McLean married Chris Wilford in 2000. They divorced in 2006. In May 2008, McLean married Sean Berkowitz, a partner with Latham & Watkins. Berkowitz is the former Director of the Enron Task Force; they met through their mutual connection to that case.