As he walks into the courtroom at 9:30 a.m. each day of his trial, Donald J. Trump scans the benches for familiar faces.

He has glared at George Conway, an antagonist who is reporting on the former president’s criminal case for The Atlantic magazine. He smiled at Greg Kelly, a reliably pro-Trump host on Newsmax, who was in court on Thursday.

And then there are the people he has brought with him as guests. Senator Rick Scott of Florida was there to show support on Thursday. Several days ago, Mr. Trump was accompanied by Ken Paxton, the attorney general of Texas, and David McIntosh, the head of the anti-tax Club for Growth.

During excruciating testimony about a story of extramarital sex, Mr. Trump’s son Eric was one of his sources of support, sitting behind him in court.

People close to Mr. Trump have worried about whether long days in the courtroom have had an effect on his mental state. He has been forced to sit silently for hours as witnesses like Stormy Daniels, the porn star whose story of a liaison set the case in motion, have insulted him in deeply personal ways. Before the trial, Mr. Trump’s advisers discussed the need to have people who Mr. Trump finds supportive nearby when he looks back from the defense table — both for his sake and so that jurors can see he has people standing with him.

A growing number of allies have heeded the call. During the rare breaks when he doesn’t leave the courtroom, Mr. Trump occasionally turns around from the defense table and scans the room.