Billionaire philanthropist Robert Smith, seen in 2016, says he’s paying off student loans for the Class of 2019 at Morehouse College.

Billionaire Robert Smith woke up the crowd at Morehouse College commencement ceremony when he veered off script to share a surprise: He’d be paying off all the student loans for the Class of 2019’s nearly 400 graduates.

There was a moment of stunned silence before the grads and their families burst into a joyous applause. Within minutes, praise for Smith spread beyond Morehouse and turned into one of last weekend’s most inspiring stories.

The billionaire tech executive and philanthropist has kept under the radar much of his career, even in Austin, where he lives and works. He rarely grants interviews and is so low-profile that when the Smithsonian’s National Museum of African American History and Culture put a call out for major donors in 2013, the museum’s directors wondered, “Who is this Robert F. Smith?” They got their answer in spectacular fashion.

Here are things you need to know about Robert F. Smith:

A knack for computers led to his fortune

As a junior in high school, Smith landed an internship at Bell Labs — by calling the company every week for five months until he got a slot. Smith tinkered with computers during his summer and Christmas breaks, and went on study chemical engineering at Cornell University. He earned an MBA from Columbia University, followed by an investment banking job at Goldman Sachs. After advising billion-dollar mergers for tech companies like Microsoft and Apple, he left Goldman to found Vista Equity Partners 2000. He is still the chairman and CEO.

The firm invests in software and data companies and now has more than $46 billion in assets, according to Forbes. As of Monday, Forbes put Smith’s net worth at $5 billion. He is the nation’s richest black man.

Major donor to the National Museum of African American History and Culture

Before the museum opened, Smith pledged a $20 million gift (behind Oprah’s $21 million pledge).

Smith’s donation to the African American history museum was earmarked to digitize photographs, videos and music — and help foster an interactive experience for a 21st-century museum. The gift also allows the museum to act as a hub to archive photographs from other institutions, like museums, funeral homes or personal collections.

Other major donations

Before last Sunday’s graduation speech, Smith had donated $1.5 million to Morehouse for scholarships and a new park. In 2016, Smith and the Fund II Foundation together gifted $50 million to Cornell University for its chemical and biomolecular engineering school, and to support black and female engineering students. (Cornell renamed the school after Smith.)

In 2017, Smith also put his name on The Giving Pledge — a commitment by the world’s wealthiest individuals and families to donate most of their wealth.

A musical upbringing

Smith grew up in a mostly black neighborhood in Denver. Both of his parents had doctorates in education and insisted that the house be filled with music — be it a live show on the house’s piano or Leontyne Price’s arias on the stereo. Smith brought that early musical influence to his eventual tech career.

“A beautifully written software code is a lyrical concerto,” he told The Post in 2016.

Smith was also the first African American to be named chairman of Carnegie Hall in New York in 2016.

An under-the-radar personal life ... in some ways

Though Smith has largely stayed out of the spotlight, he lives it up in other ways. In 2015, during his nuptials to actress and former Playboy model Hope Dworaczyk on the Amalfi Coast, the wedding singers included John Legend, Seal and Brian McKnight.

His love of music is reflected in the names of two of his sons, Hendrix and Legend — a homage to music icons Jimi Hendrix and John Legend. Smith also reportedly owns one of Elton John’s old pianos.