King reached the final of the Austrian Darts Open by beating Joe Cullen in the quarterfinals 6-0 with an average of 103.66 and Steve Beaton in the semifinals 6-5. He faced Steve Beaton in the final, al nassr jersey overshooting 134 at a score of 4-3 for Beaton as he hit a triple 20 on his last dart instead of a single to make 40 stand. Michael van Gerwen made short work of the 0:6 in the final. King led 3-0 and 4-1 in the final but only won three more legs from there and lost the match 4-6. King later revealed that the audience influenced his performance, as they loudly booed his shots at doubles. King won all three of his group matches at the Grand Slam of Darts but was defeated 5-10 by Kevin Painter in the round of 16. At Herta's first stop there were problems refueling which made the stop last 25 seconds (around 7 seconds normally) and he lost many places. The remainder of 2015 proved disappointing for King as he was eliminated in the first round of the World Matchplay, World Grand Prix, European Championship and Players Championship Finals and failed to get out of his group at the Grand Slam.

King's first final of the year came at the Dutch Darts Masters in February, but he was defeated by Michael van Gerwen 6-4 while averaging 107.40 points. He made it to the semi-finals of the Dutch Darts Masters, where he recovered from a 5-0 win against Benito van de Pas in the quarter-finals and won 6-5. King's second European Tour final of the year came at the German Darts Masters in September, where he defeated Peter Wright 6-5 in the third round, defeated James Wade 6-0 in the quarter-finals and defeated Wayne Jones 6-6. 4 defeated. He also played van Gerwen in the third round of the UK Open and was again defeated 5-9. King continued his fine form at the Masters by defeating Simon Whitlock and Justin Pipe and then put in an excellent performance, beating van Gerwen 11-9 with a 121 finish on the bullseye.

Round 6:10 against Justin Pipe and then complained of tennis elbow. At the UK Open, King beat his old BDO rivals Ted Hankey and Gareth Cousins ​​before losing 7-9 to van Gerwen. In September, King ended a string of European Tour Finals losses and won the European Darts Grand Prix by beating Michael Smith 6-5. He met van Gerwen again in the final and was dealt with 3:6. However, he was intercepted in the second round for the third straight game as he was beaten 4-1 by Michael van Gerwen. King came back from 2-0 down in the first set to win it and was in control of the match from then on, ultimately winning 5-2 to advance to the final against Michael van Gerwen. He carried the momentum into the final against James Wade and was leading 5-0 before the first break and playing an average of 110. Later he was leading 9-2. Wade rallied and closed the gap to 9-6 before King shone with a 158 finish and was one leg away from his first PDC Major title.

King played Geoff Kime in the first round of the 2012 World Championship and outplayed his opponent by winning 3-0 without giving up a leg. Due to dropping out of the top 16 of the PDC ranking list, King had to play seeded Phil Taylor in the first round of the 2012 World Matchplay. King played his first final of the year at the eighth UK Open qualifier in April after winning seven games including victories over James Wade, Wes Newton and Robert Thornton. But he then missed eight championship darts and Wade was able to complete his comeback with an 11-10 win. At the World Grand Prix in October, King reached his first grand final in two years. The mistakes didn't seem to affect him in the Grand Slam as he punished every mistake made by Gary Anderson in his 10-4 win in the round of 16, then defeated Stephen Bunting 16-9 to face Phil Taylor in the semifinals. King showed great mental toughness at the UK Open to defeat Gary Anderson 9-8 after trailing 8-4 and witnessing 13 match darts from Anderson. He then emerged successfully from a decision leg for the third straight season, defeating Kyle Anderson 9-8 to advance to the quarterfinals. He lost in the semifinals to Phil Taylor 8-10. He later lost 9-5 to Mark Walsh in the third round of the 2011 UK Open.