As a mime using the moniker of Tape Face, formerly known as The Boy With Tape On His Face, Wills won a hotly contested fan vote to advance.
"I wasn't expecting you to be the number one pick," stated notoriously harsh judge Simon Cowell.
"But I am thrilled that you are in the final. You are nuts and I'm looking forward to seeing what you do next.
The performance that got Tape Face through involved balloons, staple guns and an audience member:
Canterbury-native Wills received a unanimous "yes" from all of the judges after his debut on the show in June.
His performing career started as a busker in Christchurch. He then won the The Press People's Choice Award at the World Buskers Festival in 2008.
The Boy with Tape on his Face show developed from there, and he has sold out shows around the world.
He will perform again at the America's Got Talent finals on September 13.