The school reversed the policy Monday and agreed to pay the legal costs of Crystal Seifferly, the American Civil Liberties Union said.
The ACLU took the Lincoln Park Public Schools to court over the ban.
At a March 2 hearing before U.S. District Judge Gerald Rosen in Detroit, it said the district's policy violated the honor student's religious rights as a follower of Wicca, the witches' faith.
On Monday, the suburban district agreed to make an exception to its anti-gang policy for students who wear the five-pointed pentagram and other symbols as a profession of their religion.
"I'm happy. I'm pleased. I'm glad it's over," Seifferly said. "The longer it went on and the more I thought about it, the more I realized that it wasn't about me and just about Wicca. It was about a lot of other people and religions."