CHICAGO — After years of protests by Native Americans and pressure from the N.C.A.A., the University of Illinois in 2007 retired its mascot, Chief Illiniwek, who wore a feathered headdress and beaded buckskin to dance while the band played. The end of the chief, a university official said at the time, was a chance to “move our institution forward.”

Yet more than a decade later, an unofficial Chief Illiniwek still makes appearances around campus. Anti-chief protesters blocked a homecoming parade last October. And just last week, a professor opposed to the mascot was arrested at the campus basketball arena after searching in a bathroom for Chief Illiniwek.

Major League Baseball announced this week that the Cleveland Indians would stop using the team’s cartoonish Chief Wahoo logo on uniforms next year, but similar moves by professional teams and colleges around the country in recent years have rarely proved to be simple or absolute. Decisions to end the use of Native American imagery out of concerns about perpetuating racist and offensive stereotypes have run up against protracted battles with alumni groups and fans, who say they are attached to their team’s symbols and often insist that they are intended to honor indigenous people.

State legislators once tried to block the University of North Dakota from dropping its Fighting Sioux nickname during a bitter, yearslong fight over the matter. At Marquette University in Milwaukee, trustees were widely mocked for trying at one point to nickname their teams “the Gold” in an effort to calm alumni who were demanding that an old name, the Warriors, be restored.