(CNN) -- A kid raised in a middle-class Boston suburb, Michael Bloomberg took out loans to pay for his tuition at Johns Hopkins University and worked as a parking lot attendant.
He learned early to pay it forward.
Bloomberg's first gift to his alma mater was a whopping $5 in 1965, a year after he graduated with a bachelor's degree in engineering.
Fast forward to Saturday, when the Baltimore university announced Bloomberg has now given a total of $1.1 billion. The latest commitment came in the form of a cool $350 million toward a "transformational" initiative aimed at cross-discipline solutions to societal problems.
In a statement, Johns Hopkins said Bloomberg, a former trustee, is believed to be the first person to ever reach the $1 billion level of giving to a single U.S. institution of higher education.
The university's Twitter feed was aglow with information on the gift. One tweet heralded the announcement with the words, "Big News," which might have been an understatement.
Among other things, the donation will fund 2,600 Bloomberg Scholarships over 10 years and 50 distinguished scholars.
Of the $350 million, $100 million will go toward "need-based financial aid" for undergraduate students.
"Johns Hopkins University has been an important part of my life since I first set foot on campus more than five decades ago," Bloomberg said in the press release. "Each dollar I have given has been well-spent improving the institution and, just as importantly, making its education available to students who might otherwise not be able to afford it."
The remarkable tally speaks to the generosity and success of New York City's mayor, who grew a business empire after leaving Baltimore. He will turn 71 on Valentine's Day.
Bloomberg earned an MBA from Harvard Business School. He was hired by the Wall Street firm Salomon Brothers in 1966, according to his biography on NYC's website.
After he was let go from Salomon when it was acquired in 1981, the budding entrepreneur used his information systems expertise to launch Bloomberg LP, which provided advanced computer systems for traders and financial firms. Bloomberg's media interests followed and the company now has more than 15,000 employees worldwide, according to his biography.
Bloomberg eventually devoted his energies to philanthropy and politics. He was elected mayor of the Big Apple in 2001 and has held the office since.
His first $1 million commitment to Johns Hopkins was made in 1984, 20 years after graduation, in honor of his mother, Charlotte.
The university's president, Ronald J. Daniels, said Saturday's announced gift "illustrates Mike's passion for fixing big problems quickly and efficiently. It will ensure not only that Johns Hopkins helps to solve humanity's problems, but also that it leads the world's universities in showing how it should be done."
The mayor's overall giving includes $240 million for capital and infrastructure improvements, $219 million for student financial aid and $336 million for research.
"Giving is only meaningful if the money will make a difference in people's lives," said Bloomberg. "And I know of no other institution that can make a bigger difference in lives around the world through its groundbreaking research -- especially in the field of public health."
CNN's Erinn Cawthon and Phil Gast contributed to this report.