The 33-year-old halfback informed teammates of his decision on Monday, with the club announcing the news a short time later.
"This is a decision that I've sat with for a while now and one I'm probably still coming to terms with," Johnson said as he addressed the Warriors playing group.
"It's obviously still very raw but I'm so grateful to the club and to you boys who I get to come into work with every day with a smile on face. I have never taken any of it for granted."
Johnson is set to retire as the fourth-most capped Warriors player of all time behind only Simon Mannering, Stacey Jones and Manu Vatuvei, as well as the club's most prolific points scorer.
If he plays in all four of the Warriors' remaining games, he will finish with 269 career appearances, 225 of those for the Kiwi club and the remainder for Cronulla.
Johnson is likely to be best remembered for steering the Warriors to their second grand final appearance as a fleet-footed rookie halfback in 2011.
More recently, he experienced a sharp uptick in form to guide the Warriors to a fairytale preliminary final berth during Andrew Webster's first season as coach last year.
Shaun Johnson sights a gap during last weekend's clash against Parramatta. (Andrew Cornaga/AAP PHOTOS)
He was crowned Dally M Halfback of the Year at the end of 2023, with Newcastle's Kalyn Ponga beating him to the Dally M Medal by only one point.
Johnson won plaudits for developing his game from livewire running threat to mature game manager later in his career, but a persistent achilles injury has hampered his 2024 campaign.
Five points out of the top eight with five rounds remaining, the Warriors look set to miss finals this season which would leave Johnson's last appearance for the club as the round-26 clash against his former club Cronulla.
The Warriors plan to farewell Johnson against Canterbury in round 25, when he will play his last home game.
"There's an entire generation of kids in this country who picked up a rugby league ball because of Shaun Johnson," said Warriors chief executive Cameron George.
"His impact on not only this club but also rugby league is New Zealand is something that will be remembered here forever."
Johnson retires having played 32 Tests for New Zealand, including the victory over Australia in the 2014 Four Nations final.
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