The White House announced the switch late Thursday.
Norris was part of the team that led the Obama campaign to victory in the Iowa caucuses. She will now serve as a senior adviser to the Corporation for National and Community Service.
"I am grateful to President and Mrs. Obama for the opportunities and friendship they have given me over the last few years and I am looking forward to becoming an integral part of this Administration's efforts to advance the cause of national and community service," Norris said in a statement released by the White House.
In a statement, Mrs. Obama described Sher, who has been advising her on issues like health care, "as a trusted advisor, longtime mentor and friend dating back to my work at the City of Chicago and later the University of Chicago."
She also thanked Norris for building "a strong organization in the East Wing."
The first lady is slated to join President Barack Obama in Europe for the final leg of his latest overseas trip.