His uncle was bushman Rod Ansell, who inspired the film Crocodile Dundee (1986). Rod was married to Liam's aunt (Liam's mother's sister), Joanne van Os, who is an author.
Before his career in acting took off, he worked some odd jobs that included laying floors, nature park ranger, bakery assistant and bowling alley employee.
Ranked the #3 "Sexiest Man" in 2013 by "Glamour", several places ahead of his older brother Chris Hemsworth who ranked at #7.
His maternal grandfather, Martin van Os, is a Dutch immigrant. The rest of his ancestry is Irish, English, and smaller amounts of German and Scottish.