Substitute Glenn Murray headed a half-cleared corner into an open net within just seconds of being on the pitch to secure a historic Premier League victory for the Cherries.
It was the hosts that went forward first, and Eden Hazard ensured that Artur Boruc was on his toes early on. But the Poland international beat away the diminutive forward's opening shot.
Adam Smith and Harry Arter then hounded the Belgian down in his own half before crossing for Junior Stanislas, but his strike was blocked by Gary Cahill.
A cleared Chelsea attack then freed King and Stanislas to attack once more, but Stanislas’ initial shot was palmed away by Courtois before King’s rebound was blocked and cleared.
The Norwegian international then had another opportunity moments later. Dan Gosling slipped him in to fire a low strike at Courtois, but the Chelsea ‘keeper was again equal to the effort.
With just ten minutes to play before the interval the hosts burst into action, and Hazard twisted on the edge of the penalty area and forced a fine save from a fully stretched Boruc.
The Cherries weren’t quite done for the first half yet, either. A half cleared ball teed up King on the edge of the penalty area, but the forward’s curled effort flew just over the Chelsea crossbar.
King continued to cause the home defence hassle after the break. The former Manchester United man burst into the penalty area and cut back for Matt Ritchie, but his strike from range fell just wide of the mark.
Chelsea then had a real chance to take the lead as Willian delivered a dangerous cross from the right. But Nemanja Matic was unable to keep his header down and it soared over from close range.
Jose Mourinho's men continued to cause the Cherries trouble down the right flank. Matic, from the edge of the penalty area, played a dangerous ball across the AFC Bournemouth goal line, but Smith was on hand to clear the danger.
With ten minutes to play Eddie Howe made his first substitution of the evening, as summer signing Murray replaced the injured King.
The substitute made an immediate impact. A Stanislas corner was hooked back towards the near post by Steve Cook and Murray headed home into an empty net to send the Cherries fans behind the goal into raptures.
AFC Bournemouth almost doubled the score line shortly after. Murray turned provider and flicked the ball into the path of the onrushing Ritchie who bore down on the Chelsea goal, but his strike crashed into Courtois' side netting.
In the dying moments of the match Arter and Gosling also had opportunities to add to the score line, but despite being unable to convert these the Cherries held on for a well deserved 1-0 win.
Cherries: Boruc, Francis, Cook, Daniels, Smith, Gosling, Arter, Surman, Stanislas, Ritchie, King (Murray, 80)
Not used: Allsop, Cargill, Butcher, O’Kane, Kermorgant, Rantie