Boxing under the guidance of Sab Leo for Hoddesdon BC, he defeated Toby Bassett, former East Midlands and Northwest champion, with a mature performance in what was his 48th win as an amateur.
The first round saw King box on the back foot against an opponent who was looking for a brawl.
With this in mind, the Lutonian made the ring big, picking off Bassett at every opportunity with a display of accurate shots.
As the bell neared, King landed two heavy right hands to secure the round, while he continued to show the maturity to outbox Bassett in the second.
The third and final round saw King switch up his tactics and come out on the front foot, meeting Bassett in the centre of the ring.
Both fighters had successes whilst trading, however, it was clearly tjhe Lutonian landing the heavier, more precise shots, which saw him go on to win his ninth Home Counties title.
Speaking after the bout, King, who has recently returned from Los Angeles after spending time training there at Tengoose Boxing gym under the guidance of world renowned trainer Ricky Funez, said: “I am pleased with my win against a tough opponent and how my boxing career is shaping up.
“I am 21 now and I feel that I have been really well schooled over the last 11 years as an amateur and I just want to carry on gaining experience.
“I have spent a lot of time over the past few weeks getting the very best top class sparring and I am working on different aspects of my own boxing style.
“I am really looking forward to what the future in my boxing career brings.”