Wakefield-born Macgraff is the latest member of the Leuluai dynasty to play in this country.
Although having come through the junior ranks with the Auckland Sea Lions, Sydney Roosters and Newcastle Knights, the Second Row, capped at Under 16 level for New Zealand, made his senior bow with Leigh.
Having demonstrated his potential with the Centurions he moved to Widnes in 2011, enjoying a successful year which culminated in him being selected in the Championship All Star team.
His performances also earned him a contract for 2012, but he was restricted to 11 appearances.
Macgraff is sponsored by MSP Motors Ltd for Super League 2013.
Previous Club: Leigh
Widnes debut: London Skolars (A) 6th February 2011
Career record as at 31st October 2012: 75 apps; 14 tries; 56 points