Mills began her acting career as a child, winning the BAFTA Award for Most
Promising Newcomer for Tiger Bay (1959), the Academy Juvenile Award for
Pollyanna (1960) and Golden Globe Award for New Star of the Year/Actress
in 1961. During her early career, she appeared in several Walt Disney films
and is perhaps best known for her dual role as twins Susan and Sharon in
the Disney production The Parent Trap (1961). Hayley is the daughter of
Sir John Mills and the sister of actress Juliet Mills.