The 22-year old South Korean attacking midfielder joined the Championship outfit from Cerezo Osaka last week on a three-year deal but the manager of the Welsh club has revealed that a top flight team tried to swoop for him prior to committing.
"There was strong interest from others and a Premier League club stepped in last week but the player had already committed to Cardiff by then and we were absolutely delighted by that," Mackay told Wales Online.
"We have had strong recommendations from our contacts in South Korea, including an English coach, because Kim is an up-and-coming force.
"This one is really exciting. Kim is going to be the next big thing out of South Korea and will win many international caps for his country.
"He has the potential to be something special."