The South Africa-based businessman previously spent more than a decade on the Ibrox board under the Sir David Murray regime.
Now after talks with chief executive Craig Mather, King looks set to take charge of the club, and McCoist is delighted.
"Dave has already invested vast sums of his own money into Rangers and that tells me he's the kind of investor we need at this club again," McCoist told the Daily Record.
"The recent accounts have been well documented and the fact is we will need reinvestment at some stage in the future. If we are going to get reinvestment it would be good to get it from someone who has the best interests of the club at heart.
"Dave has and clearly the board also believe that to be the case. The fact a member of the board has flown to South Africa for talks would indicate they feel it would be hugely beneficial to have Dave back on board. It can only be a good thing for Rangers.
"I believe the board deserve credit for making such an effort to attract someone like Dave back to the club.
"This is a message that they are trying to do their best for Rangers.
"They have a difficult and important job to do and it is encouraging to think we are talking to someone who could help move the club forward. It would be a great thing for us all."
With King's arrival set to be confirmed before the club's annual general meeting on October 24 - it has been confirmed that non-executive director Ian Hart has left the club to pursue charitable work.
"It is with sadness that we see Ian depart from the board and we would like to thank him for his valuable contribution over the past year," said Mather.
"Ian remains a huge fan of the club and we wish him the best of success in future."