Kidder was born in Yellowknife, Northwest Territories, Canada. She studied at Havergal College in Toronto. From 1975 to 1978, she was married to Thomas McGuane. From 1979 to 1980, Kidder was married to John Heard, for a total of six days. From 1983 to 1984, Kidder was married to Philippe de Broca. She had one child.