Last year, she proved wrong all those who had dismissed her as a neophyte with a big mouth. The seven-day teachers’ strike she pulled off in September secured her 29,000 devoted union members a contract that delivered much of what they wanted. Just as important, it established her as someone with the stature to go toe to toe with Rahm. He won’t be able to close a school without Lewis watching his every move—and getting reporters, parents, and community activists to pay attention too.

Photograph: TOM MADAY