Williams brings a lot of experience to Elland Road, having spent almost 27 years at Chelsea, where he worked in a variety of other roles, including chief scout.
"I'm looking forward to working at Leeds," said Williams, who left Stamford Bridge in June. "Leeds is a big club with a massive profile, and I want to help bring success here again."
Chelsea captain John Terry, Robert Huth, Mikael Forssell and Carlton Cole are among recent stars who were first spotted by Williams and United will be hoping he can unearth simliar talents for Kevin Blackwell.