A grand jury in New Jersey dismissed charges on Wednesday against the high school principal who had been accused of endangering a student, in a racially charged case that roiled the liberal, diverse towns of South Orange and Maplewood.

The principal, Frank Sanchez, 50, remains in professional limbo. In May, with charges hanging over him, the district did not renew his contract; he remains on paid administrative leave, which ends this month. He plans to appeal the school board’s decision and…