Capello felt he had every right to select King, who had played in Spurs' last four matches and is seen by the Italian as one of the best central defenders in the country.
The England coach was perfectly aware of King's chronic knee problems but thought it important to speak with the player directly and have his own staff offer their medical assessment.
Redknapp queried the decision, claiming if the 28-year-old was picked for the Three Lions - either against Slovakia on Saturday or Ukraine next Wednesday - it would effectively prevent him playing in Tottenham's next match.
The Spurs boss then continued his attack on Tuesday, by which time King had returned to his club - with Capello informed there was no chance of him being involved in training this week and therefore playing in either game.
Capello insists he does not have a personal problem with Redknapp.
However, the Italian wonders why Redknapp has been critical of him when there has been no mention of Scotland coach George Burley picking Alan Hutton - even though the full-back returned only on Monday to reserve-team action after four months out with a foot injury.
"Harry Redknapp has spoken about the England team, but Alan Hutton is in the Scotland squad after being out for a number of months. But that has not been mentioned," said Capello.
"I do not understand why this is the case. I think I should be able to check all my players. I did it with Steven Gerrard last time - and I wanted to do it with Ledley King this time.
"He was not injured when he played for Tottenham last week, and it was important for me to speak with him and hear what my own medical people say."
Capello's admiration for the player has not been affected by his injuries - and should King ever be restored to a decent level of fitness, Redknapp would not be required to drive the player to South Africa for next year's World Cup.
"If he was going to do that he should set off now - it is a long way in a car," laughed the England boss.
"Without doubt, King is one of the best central defenders in England. If he was fit, Redknapp would not need to make the journey. King could come with us.
He said: "We hope (he has an international future), because he's a very interesting player - one of the best centre-backs. But I don't know the future.
"We've followed Ledley King a long time. The last four games he played all the games. For this reason we chose him.
"He came here. The national team's medical staff checked him. There was some problem of the knee. The day after we found the same problem with it, so we decided Ledley would return to Tottenham.
"He's a good player. I watched the game. He always plays well. When I chose I try to chose the best players.
"When the medical staff check on the situation we decided that he could go back."