Mary Jo WhiteMary Jo White headed the defense team of JPMorgan Chase when lawyers at the Securities and Exchange Commission went after the bank for misleading mortgage investors. They didn’t know that White could someday be the chair of the agency.

President Barack Obama nominated Mary Jo White to head the SEC. The president praised White’s career as the New York prosecutor who brought down John Gotti and placed terrorists in jail. He added that no one wants to mess with Mary Jo.

Some investor advocates are concerned about White’s recent stint as private-sector lawyer, specially her defense of some Wall Street giants. In November, she represented JPMorgan when it settled with the SEC. She also represented Ken Lewis in the past when he was still chief executive of Bank of America and faced a civil fraud lawsuit.

At an event at the New York University School of Law, White gave an assessment of how aggressively prosecutors should pursue Wall Street. She told the audience that it is important to distinguish between what is criminal and what is just mistaken behavior.

Observers said that her experience in prosecuting and defending corporate America makes her the right person for the job. During the announcement of her nomination Thursday, she said that she welcomes the chance to lead the SEC.

Thursday was also her wedding anniversary. Her husband of 43 years, John White, was the former head of SEC’s corporate finance division.

White became the US attorney in Manhattan in 1993. She was the first and only woman to hold the position at that time. She spent nine years as US attorney and prosecuted the terrorists responsible for the 1993 bombing of the World Trade Center and the 1998 bombings of US embassies in Africa. She left the position in 2002 and became a white-collar criminal defense attorney at Debevoise & Plimpton in New York.