When students of the Harvard Business School (HBS) elected Henry M. Paulson Jr. to speak at their Class Day, they invited the head of a Fortune 500 company, not a secretary.

Paulson, who graduated with an MBA from HBS in 1970, currently serves as the chairman and chief executive officer of the Goldman Sachs Group. He will address nearly 3,500 people at the school today in a speech that comes just a week after he was nominated by President Bush to serve as the next Treasury secretary, the post that Lawrence H. Summers held before becoming Harvard’s president.

The Senate is widely expected to confirm Paulson, and he could succeed John W. Snow at the position as early as the beginning of July.

But when students wrote down Paulson’s name last year on ballots handed out to the graduating class, they were choosing him as a representative of the private sector—not a public official.

A committee composed of four elected students from the Class of 2006 then narrowed down the list of possible speakers to 10, before choosing Paulson at the end of March.

That was two months before Paulson was chosen as the next man to sign his name on the dollar bill.

Paulson joined the Chicago office of Goldman Sachs in 1974. The investment banker rose through the ranks of the famous firm to become its top officer in 1999.

Paulson will be succeeded by Lloyd C. Blankfein ’75, a former Winthrop House resident who is currently the second-in-command at Goldman Sachs.

If Paulson is confirmed by the Senate, his departure from Wall Street and move to Washington, D.C. will be a return rather than an introduction.

Immediately out of Business School, Paulson served for the Nixon administration as an aide to the assistant secretary of defense from 1970 to 1972. He then joined the White House as staff assistant to the president until 1973.

In addition to his interests in business and politics, Paulson is also a nature enthusiast. He enjoys fly fishing and bird watching and, since 2004, Paulson has served as the chairman of the Board of Directors of the Nature Conservancy.

He is also the chairman emeritus of the Peregrine Fund, an organization devoted to protecting birds of prey in their natural habitats.

Before going into business, Paulson earned a bachelor’s degree in English from Dartmouth, where he was also an all-Ivy football lineman and a member of the academic honor society Phi Beta Kappa.

One student on the committee that picked him as speaker says she was delighted that Paulson accepted the offer.

“I think he’s a great choice,” said Pooja D. Kapadia, HBS Class of ’06. “He has obvious business credentials as well as leadership and engagement in public service.”

—Material from the Associated Press was used in the reporting of this story.

—Staff writer Claire M. Guehenno can be reached at guehenno@fas.harvard.edu.