The midfielder arrives with a respectable pedigree. Nearly 300 appearances in the top two tiers of English football, 50 caps for Wales, more than 60 career goals, a League One title, a Championship title and the small matter of a Premier League title.
Speaking earlier in the week, Rangers boss Steven Gerrard said that Rangers would only add a player to the squad "if something unique happens".
Within a matter of hours King's name was linked with a move and, after the blessing of Brendan Rodgers, he moved north.
But what does the signing mean for...
RangersFor the club in general it is another sign that they are becoming an increasingly desirable location for players.
It of course helps when you have a manager as respected as Steven Gerrard, are competing in Europe and playing in front of full houses, rather than scraping around on hands and knees in the muck, slap bang in a Banter Years era that seems inescapable.
King's comments speak volumes: "I had a conversation a couple weeks ago with Leicester about getting regular games and once I head about Rangers there was only one place I wanted to go.
"There were a few clubs interested, my agent had talks with a lot of clubs but Rangers was the only place I wanted to go to. A massive club with a great manager."
The title race
It is far too early to tell how effective King's signing is going to be and how influential he will be. He could go the way of Amdy Faye, Joey Barton, James Beattie and the cast of washouts arriving with substantial Premier League experience before stinking the place out, their legacy being that of provoking a shudder at the mere mention of their name.
Yet, Steven Gerrard has not been shy in stating that he wants two players for every position. In Steven Davis, Ryan Jack, Joe Aribo, Glen Kamara and Greg Docherty he had five for the three midfield positions.
"I said in pre-season I was wanting two strong players for every position. In the midfield area I had five but as of quarter past ten I have six now and I am delighted.
"He is hungry to play, he got an injury last year which frustrated him a lot. I spoke to him and he understands he has to work hard. But for the club and myself it is positive news.”
If Gerrard is to put up a title fight all the way to the end he will need a squad which he can rotate. Not only just having the numbers but the quality. He only has to venture back to Aberdeen in the Betfred Cup semi final, or as it should be known for eternity - the Umar Sadiq semi.
In addition, there was also Joe Worrall, Gareth McAuley, Kyle Lafferty, Jordan Rossiter and Glenn Middleton.
Rangers have upgraded and could be fighting on four fronts if they get past Legia Warsaw in the Europa League play-off.
In the last section there were five midfielders listed. One name was conspicuous by its absence: Scott Arfield.
The latter stages of the past season saw the Canadian moved into a more attacking role as one of the supporting forwards to Alfredo Morelos, playing narrow off the flank.
It is clear that the new role is now his future at Ibrox. He started 'on the right' in both matches against FC Midtjylland, as well as the league opener against Kilmarnock.
Gerrard explained the decision in April: “You’ve got to give Sean Dyche the credit for (seeing Arfield in a more advanced position of late). I played against Scott many times when he played that narrow left-sided role for Burnley.
“He’s very effective at it but he can do it from both sides. He’s a very clever individual out on the pitch, he understands tactics and he understands where to be in and out of possession."
That intelligence does mean that, if required, he can still drop back and help out in a deeper, more central role.
We may as well look at the man himself.
The 30-year-old carries around the reputation of being a goalscoring midfielder. That was once the case, especially in the nascent period of his career.
In three consecutive seasons - 2008/2009-2010/2011 - he hit double figures in the Championship and League One. Since then his highest figure has been seven back in 2012/2013.
The last couple of campaigns have been frustrating for the player with loan spells and injuries - he made just five club appearances last term - while he has operated at Premier League in the seasons previous so it is understandable that his goal return has dropped off, playing against better opposition.
He has had to evolve as a midfielder but that shouldn't mean that he won't be another goal threat for the Ibrox side. He may even return to that role in a team which dominates, sensing the opportunity to make those late runs in support or beyond.
What Gerrard is getting is a versatile midfielder who won't be pigeon-holed as a certain type of operator.
He said: "Over the course of the last 14 months I have been trying to build a squad but a lot of the guys are very young – they need leadership and guidance in the dressing room. So it was a no-brainer. Financially, as well, it made total sense. It is a season-long loan. I think Leicester have got a call back on it.
“I think he can do numerous jobs in the middle of the pitch. He can play like a Steven Davis, if you like, and control games with his passing. He can go box to box, he can play either side of a holder, left or right. "
The King signing should be bring both positive and negative news to Greg Docherty.
Gerrard's comments suggest the former Hamilton Academical star is part of his plans this season. Conversely he has slipped down the pecking order further.
He will unlikely be considered for those big games, in Europe and domestically but he has to sense that he will get opportunities, both in the league and cup, and make sure he takes his chance.
Docherty, who impressed on loan at Shrewsbury Town last season, shouldn't see himself as simply a squad player. There is definitely a role for him in certain games. Playing away to Kilmarnock, Hamilton and Livingston or in certain fixtures where it is going to be stuffy and winning seconds balls are imperative.
His energetic, direct, bulldozing approach is perfect for such situations.
In a way, he is actually the unique individual in the Rangers midfielder.