Note: This story has been updated.

Which Mary Jo White will show up as the new chair of the Securities and Exchange Commission—the tough-as-nails former federal prosecutor who made the corporate deferred prosecution agreement into an art form, or the now-fervent defender of corporations against government investigations? Probably both, say former SEC officials who know her well.

President Barack Obama’s nomination of White on Thursday still must be approved by the Senate. But some media outlets were already hailing her as a signal to Wall Street that the SEC is serious about prosecuting wrongdoing.

But Columbia University law professor Harvey Goldschmid, a former SEC commissioner as well as one-time SEC general counsel, thinks White will bring both sides of her legal career to the job. She served as the U.S. attorney in Manhattan for nine years until 2002, and since then has led the litigation defense practice at Debevoise & Plimpton in New York. She’s also served as a director of the NASDAQ stock exchange.

Calling her appointment “terrific,” Goldschmid is someone who knows her well—and in fact taught her at Columbia years ago. “She is tough and she’s pragmatic, with a first-rate mind. She is going to be demanding and will put up with no nonsense, but she’ll be fair,” he insisted.

Harvey Pitt, former SEC chairman from 2001 to 2003 and now chief executive of the global consulting firm Kalorama Partners, also has known White for many years. “I think she is brilliant, thoughtful, creative, and balanced,” he said, “and will make an excellent SEC chairman.”

Pitt, who was appointed by President George W. Bush, said it’s too early to tell how White might come down on certain issues, such as some controversial rules that are pending at the agency.

“I can say with confidence, however, that she will consider all sides of an issue, provide fair consideration of competing viewpoints, and will listen carefully to the views of her colleagues on the commission before she decides how she will approach any particular issue,” Pitt predicted.