The 25-year-old is a powerful and creative centre who is expected to add attacking edge and depth to the squad being developed at the Blues by head coach Danny Wilson.
Halaholo said: "The opportunity to join a club like Cardiff Blues, who play at a venue with such a rich history, was very appealing.
"After speaking with the coaches and understanding what they are looking for I am excited about being able to contribute next season and beyond.
"The timing was very good for me and my family and the chance to play rugby in another part of the world and experience some true Welsh culture is also exciting."
The Kiwi was first selected by the Wellington-based Hurricanes last season after impressing during the ITM Cup with Southland, topping many of the competition's attacking statistics.
The 5ft 11in centre has drawn plaudits again this campaign after Hurricanes victories over the Western Force and Southern Kings, where he made his first start of the season.
Blues head coach Wilson said: "Willis is a player we have been aware of for some time and who is really showing his ability and having a strong Super Rugby season with the Hurricanes.
"We are excited about what he will bring to the Cardiff Blues when he joins us later this year.
"Willis is a creative presence at centre and we feel his game will really suit the playing surface at BT Sport Cardiff Arms Park.
"Alongside with the likes of Rey Lee-Lo and Matthew Morgan, he will add even more attacking threat to our game.
"He is also strong defensively and is only going to get better the more he plays. He has learnt from the likes of Conrad Smith and Ma'a Nonu in recent years so is a player who is developing fast.
"I know Willis is excited about the challenge of playing northern hemisphere rugby and we look forward to welcoming him later this year once he has completed his commitments in New Zealand."
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