Marshall topped the poll in a vote involving former players, journalists and supporters from around the world, with Kiwis teammate Shaun Kenny-Dowall runner-up. It is the first time in the 25-year history of the awards that New Zealanders have occupied the top two spots.
Marshall was instrumental in the Kiwis' success during the Four-Nations, leading them to a last-gasp 16-12 final win against Australia at Brisbane last month. He is the first New Zealander to win the award since Stacey Jones in 2002.
The other nominees were Australians Paul Gallen, Billy Slater and Sam Thaiday, and English forward James Graham.
"To win this award after coming back from three shoulder reconstructions, winning the Four Nations, and having my best-ever year since I've started in the NRL, is pretty overwhelming," said Marshall, who steered the Wests Tigers into the National Rugby League finals.
"I'm pretty excited. It is something I definitely won't take for granted."
Standoff Marshall was one of five Kiwis - all backs - named in the World 13 team, selected by members of the international media.
Centre Kenny-Dowall, halfback Nathan Fien, and wingers Manu Vatuvei and Jason Nightingale were the other Kiwis to feature in the team, which also included six Australians and two Englishmen.
World 13 team
Fullback: Billy Slater (Melbourne Storm)
Wings: Jason Nightingale (St George-Illawarra Dragons), Manu Vatuvei (NZ Warriors)
Centres: Brent Tate (NZ Warriors), Shaun Kenny-Dowall (Sydney Roosters)
Standoff: Benji Marshall (Wests Tigers)
Halfback: Nathan Fien (St George-Illawarra Dragons)
Props: James Graham (St Helens), David Shillington (Canberra Raiders)
Hooker: Cameron Smith (Melbourne Storm)
Second rowers: Sam Thaiday (Brisbane Broncos), Sam Burgess (South Sydney)
Lock: Paul Gallen (Cronulla Sharks)
