The Warriors capped their regular season campaign and celebrated Mannering's 300th appearance with a tense 20-16 win over the Raiders at Mt Smart Stadium to give them a 15-9 record, tied for the second best record in the club's 24-year history.
Along the way, Tuivasa-Sheck has carved out a total of 4058 metres (fourth best in the NRL), averaging 184 metres a game including 1093 post-contact metres. In the round 23 win over Newcastle, Tuivasa-Sheck made 338 metres, while he leads the way in kick return metres (1330) and sits fifth for most tackle breaks (109).
"I want to thank everyone who played a part in choosing this award," said Tuivasa-Sheck.
"It just comes down to my team. Thank you boys for all of your support.
"It's been unreal, always coming in every day to training and competing and helping me to become a better player.
"I appreciate it, this one's for the team."
The other nominees for the Player of the Year gong were front rower Agnatius Paasi, hooker Issac Luke, bench utility Jazz Tevaga and left wing Ken Maumalo.
Meanwhile, captain James Bell collected the two awards for the Warriors' Intrust Super Premiership side – as the ISP Team Man of the Year and ISP Player of the Year.
The Warriors NRL Rookie of the Year is second rower Isaiah Papali'i while five-eighth Blake Green claimed the Clubman of the Year award in his first season in Auckland.
Long-time team manager Laurie Hale was named the Club Person of the Year and Jayden Penerate was recognised as the Sir Peter Leitch Member of the Year.
WARRIORS AWARDS 2018
Sir Peter Leitch Member of the Year - Jayden Penerata
People's Choice Award - Roger Tuivasa-Sheck
ISP Team Man of the Year - James Bell
NRL Rookie of the Year - Isaiah Papali'i
Club Person of the Year - Laurie Hale
Clubman of the Year - Blake Green
ISP Player of the Year - James Bell
NRL Player of the Year - Roger Tuivasa-Sheck (Simon Mannering Medal)
WARRIORS PLAYER OF THE YEAR 1995-2018
1995 Tea Ropati
1996 Stephen Kearney
1997 Stacey Jones
1998 Joe Vagana
1999 Jason Death
2000 Robert Mears
2001 Jerry Seuseu
2002 Ali Lauitiiti
2003 Francis Meli
2004 Wairangi Koopu
2005 Ruben Wiki
2006 Steve Price
2007 Steve Price
2008 Simon Mannering
2009 Micheal Luck
2010 Manu Vatuvei
2011 Simon Mannering
2012 Ben Matulino
2013 Simon Mannering
2014 Simon Mannering
2015 Ben Matulino
2016 Simon Mannering
2017 Roger Tuivasa-Sheck
2018 Roger Tuivasa-Sheck