Katie McWilliam was born on September 6, 1960, in Buffalo, New York. Katie married Charles "Chay" on January 16, 1993, and they had four children: Jamie, Charles "Chay" Jr., Rebecca "Becky," and Amy.
McWilliam obtained a bachelor of science and master of science degree in geology.
McWilliam was a consultant for the Nevada Test Site regarding seismological issues. McWilliam was also previously employed as a business and marketing manager.