Pearson is one of five children of Canadian diplomat Geoffrey Pearson and former Ontario Senator Landon Pearson, and the granddaughter of former Prime Minister Lester Pearson.Born in Mexico City, Pearson was educated at Netherwood School in Rothesay, New Brunswick, Trinity College, Toronto, the University of Chicago, and Columbia School of Journalism in New York.She resigned her weekly column at the National Post in 2003 to protest that newspaper's support for the Bush administration in the lead-up to the Iraq war. Pearson's subsequent satirical writing has been hailed as "hysterically funny" by the Los Angeles Times.

Pearson has lived in New York, Delhi and Moscow, and now resides in Toronto, Ontario with her husband and two children.

She has won numerous awards for her writing including:

• National Magazine Awards
• National Author's Award
• Arthur Ellis Award for best non-fiction crime book (1997)
• Stephen Leacock Memorial Medal for Humour, finalist (2003)