Invoking the names of an earlier generation of athletes who called for social justice, Mr. James, a forward for the Los Angeles Lakers, said he wanted to be a model for future generations.

In some respects, Mr. James’s activism reflects a return to an earlier generation of athletes who used their fame to speak out about racial equality and the Vietnam War with little regard to whom it might offend.

“This group of athletes wants to feel empowered in every single way,” Mr. Carter said.

Jocelyn Benson, the Michigan secretary of state, said that “trusted voices” like Mr. James’s could help break through the din at a moment of rising skepticism toward the news media and both political parties.

The group, which will be organized as a 501(c)(4) nonprofit organization and therefore not engage in specific advocacy for a candidate, is still coming together, but Mr. James said he had found only willing ears in his recruiting conversations.