Born Elizabeth (Liza) C. Sheard, she grew up in the Rosedale neighbourhood of Toronto, Ontario
Her father, the Honourable Joseph Sheard (1924–2015), was a judge who served on the Ontario County Court from 1977 until mandatory retirement in 1999; he was a graduate of the University of Toronto and Osgoode Hall Law School (class of 1951) and had served in the Royal Canadian Navy during World War II (Osgoode Society oral history)
Her father's dinnertime stories about clients and their legal problems inspired her interest in law, as they "whetted an appetite that is still in me about other people and their interesting legal problems, and their life problems" (Law Times)