Robert F. Smith was giving the commencement address to the graduating class of Morehouse College when he made a surprise announcement: He would be paying off the student loans of the roughly 400 graduates.

It was just the latest substantial gesture from Mr. Smith, the richest black man in America, who until just a few years ago was practically unknown.

Here’s what you need to know about him:

■ Mr. Smith has amassed a fortune that Forbes estimates to be worth $5 billion by founding Vista Equity Partners, a private equity firm that focuses on buying and selling software firms.

■ Vista has about $46 billion in assets under management, according to Forbes. The company is privately held and does not publicly report its results, but it is believed to be one of the best-performing firms in the country, with annualized returns of more than 20 percent since its founding.