Mills spent a decade as an executive at Madison Square Garden and before that worked at the NBA for 16 years. He left MSG in 2009 after the arrival of Donnie Walsh as Knicks president.
Grunwald replaced Walsh in 2011 and constructed much of the roster that helped the Knicks win a playoff series last season for the first time since 2000. The Knicks said in a release Thursday that he will remain with the organization as an adviser.
Source: Associated Press