King overcame Darin Young and Ricky Evans to face Adrian Lewis in the third round of the 2014 World Championship. He lost nine of the first eleven legs and could never recover as he was beaten 4–1 in sets. King's first final of the year came in February at the Dutch Darts Masters, but he was defeated 6–4 by Michael van Gerwen whilst averaging 107.40. Despite playing with a bad sciatica in his back, King reached the semi-finals of the UK Open for the first time in his career. He fell 3–0 down to Lewis and was denied a place in the final with a 10–6 defeat. In the first round of the World Matchplay, King was 5–4 ahead of Kim Huybrechts and then won five legs in a row to advance 10–4 with an average of 101.06. He could not replicate his form in the next round however, as he averaged 89.59 in a 13–8 loss to Lewis. In September, King ended a run of three defeats in European Tour finals to win the European Darts Grand Prix by beating Michael Smith 6–5.