As Nasiah Wanganeen-Milera dragged the Saints to a 13.15 (93) to 8.14 (62) win with another Marvel Stadium masterclass, the club's golden hope up forward was unable to finish the match.
King played less than 50 per cent of the game before leaving the field in the third quarter with hamstring tightness.
He went to the rooms with medical staff and failed to appear again, with the Saints ruling him out at the start of the final term.
The 26-year-old earned just two possessions, including missing a difficult shot on goal in the second term.
It was King's first AFL game since June 30, 2024, having battled knee injuries as well as soft-tissue concerns.
He had two games at VFL level earlier in the year, but suffered a hamstring injury in one of those, pushing back his comeback past the two-year mark.
St Kilda (9-10) finish the round placed 10th, in a wildcard spot ahead of the final month of the season.
But if they are to be any hope of progressing past that stage of the finals, the Saints would love a fit-and-firing King up forward.
After starting strongly with a 16-point lead at quarter-time, St Kilda were fortunate not to be further behind than a goal during the third term.
The Kangaroos butchered numerous gettable chances in front of goal all day, with Wanganeen-Milera's switch to deep forward reaping rewards for the Saints.
Nearly a year to the day since he inspired St Kilda to a famous comeback against Melbourne, Wanganeen-Milera produced a third quarter for the ages when he kicked three goals from 10 touches.
He inexplicably didn't poll three votes for his performance against the Demons last year, but the 23-year-old will surely have to earn the maximum this time for his four-goal, 46-possession domination of the Kangaroos.
Wanganeen-Milera also registered 1062 metres gained - more than half a kilometre greater than the game's next best, Saints' Darcy Wilson (489).
St Kilda were rocked by two late changes, pulling out Cooper Sharman (managed) an hour before the start, while ruckman Rowan Marshall suffered back spasms in the warm-up.
After a season of steady improvement, the Kangaroos' campaign appears shot as they sit a game and significant percentage outside the top-10.
Veteran Jack Darling capitalised up forward with three goals, but captain Nick Larkey continues to suffer the yips.
Once arguably the safest set shot in the AFL, Larkey has managed 6.15 in his past six games in a dramatic drop-off in form.
Larkey had North's first set shot of the game, spraying it badly.
From there, the Kangaroos went to 1.9, before young star Harry Sheezel kicked North's second goal midway through the second term.
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