As a coach, he took Pontypridd to two Cup finals, losing the first one in the 88th minute and winning the second at the death. Now he is hoping to take his new club, Aberavon, to their first final since 1975.
But standing in his side's way are some familiar opponents in the shape of his former club, Pontypridd. Twice King led Ponty to the Millennium Stadium, but he vows there will be no room for sentiment on Saturday.
"A lot of people have asked me if I will have mixed feelings this weekend. The answer is a simple one: I'm coach of Aberavon and I want the Wizards to win," said King
"Pontypridd have a huge cup tradition, but so too do Aberavon when you delve into their past. They were runners up in 1974 and 1975 and semi-finalists when I took Pontypridd to their first final.
"What we are trying to do is rekindle those great cup days at the club. The buzz around the players and the fans is fantastic and we are looking for a great day out on Saturday."
King is unperturbed by his side's recent Premiership defeats by Cross Keys and Ebbw Vale - the latter avenging their cup quarter-final reverse by the Wizards - and is hoping his team will be in the right physical and mental shape to express themselves in the pressure-cooker atmosphere of a cup semi-final.
"It is in games like this that you see which players can best react under pressure. It will be a marvellous learning experience for our young players," said King. "If you take Richard Morris out of the equation, and he is only 32, the majority of our team are under 25. We even have a 17-year-old in the side, Ashley Beck.
"We may have lost our points machine, Jamie Davies, but whoever plays out of James Garland and Ricky Thomas at No.10 will do a great job for us. The margins for error at this level are very small and this is a massive opportunity for one team to make a real impression. We've trained well this week and we're looking forward to taking our chance."
King knows the Pontypridd players and coaching staff inside out. But they also know what to expect from him.
"I've had a couple of conversations with Paul John, the Ponty Coach, about Saturday and we are good mates," said King. "I'm sure he and Dale McIntosh will prepare their side well and will do their homework on us. We are one win each in the Premiership, so this will be something of a decider.
"We've got here the hard way by beating the reigning champions, Llandovery, Cardiff and Ebbw Vale. We all know what to expect from Pontypridd and I'm sure they won't disappoint us."
Admission prices are £10 for Adults and £5 for Under 16s and OAPs. Tickets are available now from participating Clubs and will also be sold on matchday.
Aberavon v Pontypridd - Saturday, 26th April - Kick-Off 5.30pm - Cardiff RFC
Aberavon: Richard Carter; Steve Davies, Liam Gadd, Ashley Beck, Paul Bamsey; Ricky Thomas, Chris Morgan; Lloyd Howells, Chris Wells, Anthony Edwards, Ian Moore, Andrew Fisher, Justin Tipuric, Chris Davies, Richard Morris
Replacements: Neil White, Marc Breeze, Paul Breeze, Chris Gittins, Daryl Thomas, Gavin Hopper, James Garland
Pontypridd: Lawrence Price; Chris Baker, Gavin Dacey, Adam Thomas, Chris Clayton; Gareth McCarthy, Andrew Jenkins; Ian Pooley, Duane Goodfield, Sam Hobbs, Chris Dicomedis, Ryan Savage, Lee Evans, Wayne O'Connor, Nathan Strong
Replacements: Owen Cotton, Rhys Williams, Grant Harrington, Rhys Shellard, Geraint Lewis, Tom Riley, Neil Burnett