Over the years, Mr. Trump has billed himself as an “ardent philanthropist,” and his official biography says that he is “involved with numerous civic and charitable organizations.”

But the depiction of Mr. Trump as a generous benefactor has recently come into question amid a series of reports raising doubts about whether he has followed through on his lavish pledges, whether he misused the foundation that bears his name and whether he financially supports it at all.

Interviews with people who have worked with or solicited money from him, as well as years of publicly available charity records, paint a picture of Mr. Trump as a reluctant giver despite his wealth. Donations from his foundation, which in recent years has been exclusively financed by others, sometimes served his own needs while helping the recipients.

Jack O’Donnell, who was president and chief operating officer of Trump Plaza Hotel & Casino in the late 1980s, said Mr. Trump would question the need for donations, even those as small as a couple thousand dollars.

“He’d say ‘Why are we doing this?’ or ‘Do we have to give this much?’ ” said Mr. O’Donnell, who parted ways with Mr. Trump on bad terms and was described by the Trump campaign as a disgruntled former employee. “I don’t know how else to put it: He’s cheap.”