Kathryn Karcher was born in London, England, after which her family lived in Pakistan and India while her father worked as a medical doctor in Presbyterian Church hospitals. She learned Urdu while overseas. The Karcher family eventually moved to the small town of Hemet, California, where Ms. Karcher lived until attending UCSD. She lived in San Diego until 2005 except for three years in Los Angeles at UCLA School of Law.

Ms. Karcher rode her bicycle across the United States after completing law school, starting at the coastline in Florence, Oregon, and ending in Boston. She has practiced law ever since, joining the then-San Diego firm of Gray Cary Ames & Frye in 1989.

In 2005, Ms. Karcher married Jeff Harmes and moved to Bainbridge Island, Washington, where she continued to practice with Gray Cary successor DLA Piper. In 2008 she opened her own practice. Since then she has maintained offices in San Diego and on Bainbridge Island.

Ms. Karcher and Mr. Harmes have five adult children. Three graduated from the University of Washington and a fourth graduated from Portland State University.