Universities and private schools have established networks of former pupils in a wide range of careers to pass on their experience and offer work placements.
But the practice has never taken off in the state sector.
Liberal Democrat Mr Williams said:
"I'm delighted to help the educational charity, Future First connect Parliamentarians and all of the staff on the estate with their old state schools.
"Saying 'I went to the same school as you and now I have a job in Parliament' will show young people that they too can succeed, no matter what their backgrounds are."