Rangers secured their 10th signing of the summer on Friday with King joining on a season-long loan.
The Wales international, who has 50 caps for his country, becomes the third central midfielder signed in the current window after Joe Aribo and Steven Davis, who rejoined the Gers permanently after a six-month loan stint last term.
King offers a wealth of experience to Gerrard’s side having made 379 appearances, scoring 62 goals, in 12 years at the King Power Stadium.
But the 30-year-old has fallen out of favour for the Foxes and has no major role to play under Brendan Rodgers.
Yet Gerrard was full of praise for King, who made 25 Premier League appearances when Leicester won the league in 2015-16.
The Liverpudlian coach said: “It was a fantastic offer we had to grab. One, he is a winner, a Premier League winner. Two, because he has had numerous caps at international level.
“A lot of the guys are very young – they need leadership and guidance in the dressing room. So it [the move] was a no brainer.”
But Celtic legend McNamara, who spent 10 years as a player at Parkhead, disagrees.
“Rangers have got many midfielders at the moment,” he told Football Insider.
“I don’t think that’s a position they’re very light in.
“They need different positions there rather than in the midfield, it’s a very strange one they’d go for another midfielder.
“Only Gerrard knows. He’s not played a lot of football at Leicester, so he’ll know something about him because we’ve not seen him for the last couple of seasons.”
King admitted after sealing his move to Ibrox that he didn’t need long to make a decision on the switch.
“I’m delighted to be here; the size of the club and the manager speaks for itself,” he told Rangers TV.
“I had a few options, but when a club the size of Rangers comes in, it makes the decision really easy.
“I wanted to come here and have a real chance to try to win various amounts of silverware and hopefully play in European competitions. That was a massive pull for me.”
King was in the stands last night as Rangers defeated Danish outfit FC Midtjylland 3-1 in the second leg of their Europa League third-round qualifying clash, winning 7-1 on aggregate.
With Rangers 180 minutes from reaching the competition’s group stage for a second successive season, Gerrard’s charges will now take on Poland’s Legia Warsaw in the play-off round. The first leg takes place in the Polish capital next Thursday (7pm).
Before then, the Light Blues face East Fife in the second round of the Scottish League Cup – which Rangers have not won since 2010 – today (3pm).