Her father is a used car salesman and mother is a Canadian schoolteacher and former stage actress.
Later, she began a relationship with Filipino actor Lou Diamond Phillips in November 1990, and the couple split in January 1994.
Tilly started dating producer Sam Simon in 1983 and the couple got married in October 1984.
She has an older brother Steve Tilly and two younger sisters Meg Tilly and Rebecca Tilly.