The Royals announced on Friday that Matheny will serve as a special adviser for player development.
Kansas City general manager Dayton Moore issued a statement on Matheny's hiring included in the announcement:
"This is a great opportunity to have Mike become a member of our organization. It has always been our policy to hire the best baseball people we can and this is the perfect example of that. Mike has contributed so much to our game as both a player and a manager and has a wealth of knowledge that can only make us better. I'm excited about the possibilities of what he'll bring to our organization."
Matheny previously spent seven seasons managing the St. Louis Cardinals from 2012 to '18. He was fired by the team in July after a 47-46 start.
The 48-year-old Matheny went 591-474, made the playoffs in each of his first four seasons with the Cardinals and reached the World Series in 2013.
Prior to his managerial career, Matheny spent 13 seasons in the big leagues with four teams and won four Gold Glove awards as a catcher.
The Royals are looking for any potential advantage after finishing the 2018 season last in the American League Central with a 58-104 record.