The presumptive GOP nominee was asked Sunday on CBS' "Face the Nation" if a Muslim judge also would treat him unfairly due to his proposal to ban Muslims from entering the United States.
"It's possible, yes," Trump said. "Yes. That would be possible, absolutely."
Trump is already under fire for his assertion that the Mexican parentage of Judge Gonzalo Curiel has colored his rulings in lawsuits against Trump's business school, given Trump's claim he'll build a wall on the U.S.-Mexico border.
Pressed on whether his position is a break from the American tradition of not judging people based on where they or their parents come from, Trump said: "I'm not talking about tradition."
"I`m talking about common sense. OK? He`s somebody -- he is proud of his heritage. And I think that`s great that he`s proud of his heritage," Trump said.
He insisted the lawsuits against Trump University should have been thrown out in a summary judgment.
"He`s not treating me fair," he said of Curiel. "He`s not treating me fairly."
Trump spokeswoman Katrina Pierson defended Trump's remarks in an interview with CNN's Wolf Blitzer on Sunday, arguing that a judge's heritage is relevant in cases of "activism."
"Look, Americans aren't stupid. They know judicial activism is very active in this country," she said. "We've also seen a number of times, because CNN has given a platform to 'Black Lives Matter,' that ethnicity does matter in the current judicial system."
Asked if a judge's race, religion and ethnic heritage would play a role in whether Trump thinks that judge could be fair, Pierson said: "If it's coupled with activism, which is the key term here, then absolutely."