In the early 1970s John was living in Leichhardt and met Mary-Kay Price. Her parents had farmed on Tulloona Plain between Moree and Goondiwindi, and her father was a World War II soldier-settler. In 1973, Williamson married Mary-Kay on her parents' farm. The couple have two daughters, Ami and Georgie. Ami recalled "hen Dad was away, he was really away". Over his career Williamson has written some love songs for Mary-Kay including "Little Girl from the Dryland". On 23 April 2007, after more than 30 years of marriage, Williamson and Mary-Kay divorced. Williamson admitted that he preferred Springbrook in south-east Queensland to unwind and get inspiration for new material.