WASHINGTON--First Lady Michelle Obama new chief of staff will be Tina Tchen, a Chicago lawyer who works for Senior Advisor Valerie Jarrett as the White House Director of the Office of Public Engagement and Executive Director of the White House Council on Women and Girls, the Sun-Times was told on Wednesday.

My Sun-Times story on Tchen being tapped by Mrs. Obama to be her new chief of staff is here.

Jarrett told me in an interview that she suggested Tchen for the job to replace Susan Sher, who will be returning to Chicago at the end of the month, where her husband, Neil Cohen is a Cook County Circuit Court judge serving in Maywood.

Tchen has known Mrs. Obama for years and brings to the job "trust, confidence, knowing that Tina shares our philosophy about public service and why we are here and her enthusiasm and passion for the issues which Mrs. Obama cares deeply about and she will be a terrific bridge between the East and the West Wing," Jarrett told me in an interview.

Over at whitehouse.gov, Tchen blogs about her new--and old--position.